Expandable cage

ABSTRACT

An intervertebral implant that iterates between collapsed and expanded configurations includes first and second plates spaced from one another along a first direction and defining bone-contacting surfaces facing away from each other along the first direction. An expansion assembly is positioned between the plates with respect to the first direction and includes a first support wedge that supports the first plate and defines a first ramp and a second support wedge that supports the second plate and defines second and third ramps. The expansion assembly includes an expansion wedge defining a fourth ramp. The first, second, third, and fourth ramps are each inclined with respect to a second direction that is substantially perpendicular to the first direction. At least one of the first and second support wedges is slidable along the respective supported first or second plate. The implant includes an actuator configured to apply a drive force to the expansion wedge so as to cause 1) the fourth ramp to ride along the third ramp so as to increase a distance between the bone-contacting surfaces along the first direction, and 2) the second ramp to ride along the first ramp, thereby further increasing the distance, thereby iterating the implant from the collapsed to the expanded configuration.

TECHNICAL FIELD

The present invention relates to an expandable intervertebral implant,particularly to an implant having a pair of endplates, at least one ofwhich being independently expandable and rotatable relative to theother, and related methods.

BACKGROUND

Removal of an intervertebral disc is often desired if the discdegenerates. Spinal fusion may be used to treat such a condition andinvolves replacing a degenerative disc with a device such as a cage orother spacer that restores the height of the disc space and allows bonegrowth through the device to fuse the adjacent vertebrae. Spinal fusionattempts to restore normal spinal alignment, stabilize the spinalsegment for proper fusion, create an optimal fusion environment, andallows for early active mobilization by minimizing damage to spinalvasculature, dura, and neural elements. When spinal fusion meets theseobjectives, healing quickens and patient function, comfort and mobilityimprove. Spacer devices that are impacted into the disc space and allowgrowth of bone from adjacent vertebral bodies through the upper andlower surfaces of the implant are known in the art. Yet there continuesto be a need for devices that minimize procedural invasiveness yetstabilize the spinal segment and create an optimum space for spinalfusion.

SUMMARY

According to an embodiment of the present disclosure, an intervertebralimplant that is configured to iterate between a collapsed configurationand an expanded configuration includes a first plate and a second platespaced from one another along a first direction. The first plate definesa first bone-contacting surface and the second plate defines a secondbone-contacting surface that faces away from the first bone-contactingsurface along the first direction. The implant includes an expansionassembly disposed between the first and second plates with respect tothe first direction. The expansion assembly includes a first supportwedge that supports the first plate and defines a first ramp and asecond support wedge that supports the second plate and defines a secondramp and a third ramp. The expansion assembly includes an expansionwedge that defines a fourth ramp, wherein each of the first, second,third, and fourth ramps is inclined with respect to a second directionthat is substantially perpendicular to the first direction. At least oneof the first and second support wedges is slidable along the respectivesupported first or second plate. The implant includes an actuatorconfigured to apply a drive force to the expansion wedge so as tocause 1) the fourth ramp to ride along the third ramp so as to increasea distance between the first and second bone-contacting surfaces alongthe first direction, and 2) the second ramp to ride along the firstramp, thereby further increasing the distance, thereby iterating theimplant from the collapsed configuration to the expanded configuration.

According to another embodiment of the present disclosure, an implantfor lateral insertion into an intervertebral space includes an expansionmechanism disposed between a first endplate and a second endplate withrespect to a vertical direction. The first endplate defines a first-bonecontacting surface and the second endplate defines a secondbone-contacting surface that faces away from the first bone-contactingsurface along the vertical direction. The expansion mechanism includesan anterior actuation assembly arranged along a first axis and aposterior actuation assembly arranged along a second axis. The first andsecond axes are each oriented along a longitudinal direction that issubstantially perpendicular to the vertical direction. The first andsecond axes are spaced from one another along a transverse directionthat is substantially perpendicular to the vertical and longitudinaldirections. A first distance between the first and secondbone-contacting surfaces along the vertical direction intersects thefirst axis, and a second distance between the first and secondbone-contacting surfaces along the vertical direction intersects thesecond axis. The anterior and posterior actuation assemblies eachinclude a first support wedge that supports the first endplate and asecond support wedge that supports the second endplate and is slidablewith respect to the first support wedge. The actuation assemblies eachalso include an expansion wedge slidable with respect to the secondsupport wedge, and a drive shaft that is coupled to the expansion wedgeand is rotatable about the respective first or second axis so as tocause 1) the expansion wedge to ride along the second support wedge, and2) the second support wedge to ride along the first support wedge,thereby varying the respective first or second distance. The driveshafts of the anterior and posterior actuation assemblies are rotatableindependently of each other so as to provide a difference between thefirst and second distances.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofillustrative embodiments of the intervertebral implant of the presentapplication, will be better understood when read in conjunction with theappended drawings. For the purposes of illustrating the expandableintervertebral implant of the present application, there is shown in thedrawings illustrative embodiments. It should be understood, however,that the application is not limited to the precise arrangements andinstrumentalities shown. In the drawings:

FIG. 1 is an end view of an implant positioned between adjacentvertebral bodies, wherein the implant is in a collapsed configuration,according to a first example embodiment of the present disclosure;

FIG. 2 is a perspective view of the implant of FIG. 1, shown in thecollapsed configuration;

FIG. 3 is an end view of the implant of FIG. 1, shown in the collapsedconfiguration;

FIG. 4 is a longitudinal sectional view of the implant shown of FIG. 1,shown in the collapsed configuration;

FIG. 5 is a partially exploded, perspective view of the implant of FIG.1, with bone plates of the implant separated in a manner showing aninternal expansion mechanism of the implant in a collapsedconfiguration;

FIG. 6 is an exploded view of the implant of FIG. 1;

FIG. 7 is an enlarged view of an end portion of one of the bone platesshown in FIG. 6;

FIG. 8 is a reverse perspective view of an end portion of the other boneplate shown in FIG. 6;

FIG. 9 is a longitudinal side view of an actuation member of theexpansion mechanism shown in FIGS. 5 and 6;

FIG. 10 is a perspective view of a first expansion wedge of theexpansion assemblies shown in FIGS. 5 and 6;

FIG. 11 is another perspective view of the first expansion wedge of FIG.10;

FIG. 12 is a side view of the first expansion wedge of FIG. 10;

FIG. 13 is a perspective view of a variant of the first expansion wedgeshown in FIGS. 10 through 12;

FIG. 14 is another perspective view of the variant of the firstexpansion wedge of FIG. 13;

FIG. 15 is a side view of the variant of the first expansion wedge ofFIG. 13;

FIG. 16 is a perspective view of a second expansion wedge of theexpansion assemblies shown in FIGS. 5 and 6;

FIG. 17 is another perspective view of the second expansion wedge ofFIG. 16;

FIG. 18 is a side view of the second expansion wedge of FIG. 16;

FIG. 19 is a perspective view of a third expansion wedge of theexpansion assemblies shown in FIGS. 5 and 6;

FIG. 20 is another perspective view of the third expansion wedge of FIG.19;

FIG. 21 is a side view of the third expansion wedge of FIG. 19;

FIG. 22 is a perspective view of a fourth expansion wedge of theexpansion assemblies shown in FIGS. 5 and 6;

FIG. 23 is another perspective view of the fourth expansion wedge ofFIG. 22;

FIG. 24 is a side view of the fourth expansion wedge of FIG. 22;

FIG. 25 is a front end view of the fourth expansion wedge of FIG. 22;

FIG. 26 is a side, partial sectional view of the first and fourth wedgesduring a first phase of expansion of an expansion assembly shown inFIGS. 5 and 6;

FIG. 27 is a side, partial sectional view of the first and fourth wedgesof FIG. 26 between the first phase and a second phase of expansion ofthe expansion assembly;

FIG. 28 is a side, partial sectional view of the first and fourth wedgesduring a second phase of expansion of the expansion assembly;

FIG. 29 is a perspective view of an internal end of an expansionassembly of FIGS. 5 and 6, wherein the expansion assembly is shown in anexpanded and lordotic configuration;

FIG. 30 is a side view of an actuation assemblies shown in FIGS. 5 and6, with a proximal expansion assembly shown in a collapsed configurationand a distal expansion assembly shown in a fully expanded configurationfor comparison;

FIG. 31 is an enlarged view of the longitudinal sectional view of FIG.4, showing the implant in the collapsed configuration;

FIG. 32 is a perspective view of the implant of FIG. 1 in a partiallyexpanded configuration;

FIG. 33 is an end view of the implant shown in FIG. 32;

FIG. 34 is a longitudinal sectional view of the implant shown in FIGS.32 and 33, taken along section line 34-34 of FIG. 33;

FIG. 35 is a longitudinal sectional view of the implant of FIG. 1, shownin a fully expanded configuration;

FIG. 36 is a perspective view of the implant shown in FIG. 35;

FIG. 37 is an end view of the implant shown in FIG. 36;

FIG. 38 is a perspective view of the implant of FIG. 1, shown in apartially expanded, lordotic configuration;

FIG. 39 is a perspective view of the implant of FIG. 38, shown with abone plate removed for illustrative purposes;

FIG. 40 is an end view of the implant of FIG. 38;

FIG. 41 is an end view of a pair of wedge members of an actuationassembly shown in FIGS. 5 and 6, illustrating rotation of one of thewedge members relative to the other;

FIG. 42 is a perspective view of an implant in a collapsedconfiguration, according to a second example embodiment of the presentdisclosure;

FIG. 43 is another perspective view of the implant of FIG. 42, shownwith bone plates of the implant separated in a manner showing aninternal expansion mechanism of the implant in a collapsedconfiguration, and also with a top one of the bone plates unfolded inbook-like fashion showing internal faces of the bone plates;

FIG. 44 is a perspective view of a pair of wedge members of theexpansion mechanism of FIG. 43 positioned along a drive shaft of theexpansion mechanism;

FIG. 45 is another perspective view of the wedge members of FIG. 44,shown with one of the wedge members rotated relative to the other wedgemember about the drive shaft;

FIG. 46 is an exploded, perspective view of the wedge members of FIG.44;

FIG. 47 is a perspective view of the implant of FIG. 42 shown in a fullyexpanded configuration with one of the bone plates removed forillustrative purposes;

FIG. 48 is an end view of the implant of FIG. 42 in a lordoticconfiguration;

FIG. 49 is a partially exploded perspective view of the implant of FIG.48; and

FIG. 50 is a perspective view of a driving tool configured to expand theimplant shown in FIG. 38.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present disclosure can be understood more readily by reference tothe following detailed description taken in connection with theaccompanying figures and examples, which form a part of this disclosure.It is to be understood that this disclosure is not limited to thespecific devices, methods, applications, conditions or parametersdescribed and/or shown herein, and that the terminology used herein isfor the purpose of describing particular embodiments by way of exampleonly and is not intended to be limiting of the scope of the presentdisclosure. Also, as used in the specification including the appendedclaims, the singular forms “a,” “an,” and “the” include the plural, andreference to a particular numerical value includes at least thatparticular value, unless the context clearly dictates otherwise.

The term “plurality”, as used herein, means more than one. When a rangeof values is expressed, another embodiment includes from the oneparticular value and/or to the other particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms anotherembodiment. All ranges are inclusive and combinable.

Referring to FIG. 1, a superior vertebral body 2 and an adjacentinferior vertebral body 4 define an intervertebral space 5 extendingbetween the vertebral bodies 2, 4. The superior vertebral body 2 definessuperior vertebral surface 6, and the adjacent inferior vertebral body 4defines an inferior vertebral surface 8. The vertebral bodies 2, 4 canbe anatomically adjacent, or can be remaining vertebral bodies after anintermediate vertebral body has been removed from a location between thevertebral bodies 2, 4. The intervertebral space 5 in FIG. 1 isillustrated after a discectomy, whereby the disc material has beenremoved or at least partially removed to prepare the intervertebralspace 5 to receive an expandable intervertebral implant 10. The implant10 is shown in a collapsed configuration, in which configuration theimplant 10 can be configured for lateral insertion (i.e., along amedial-lateral trajectory) within the intervertebral space 5.

Once inserted in the intervertebral space 5, the implant 10 can beexpanded in a cranial-caudal (i.e., vertical) direction, or otherwiseiterated, between the collapsed configuration and a fully expandedconfiguration to achieve appropriate height restoration. Additionally,one of the sides of the implant 10 can be expanded vertically to agreater extent than the opposite side to achieve lordosis or kyphosis,as disclosed in more detail below.

The intervertebral space 5 can be disposed anywhere along the spine asdesired, including at the lumbar, thoracic, and cervical regions of thespine. It is to be appreciated that certain features of the implant 10can be similar to those set forth in U.S. Patent Publication No.2014/0243982 A1, published Aug. 28, 2014 in the name of Miller, theentire disclosure of which is incorporated herein by this reference.

Certain terminology is used in the following description for convenienceonly and is not limiting. The words “right”, “left”, “lower” and “upper”designate directions in the drawings to which reference is made. Thewords “inner”, “internal”, and “interior” refer to directions towardsthe geometric center of the implant 10, while the words “outer”,“external”, and “exterior” refer to directions away from the geometriccenter of the implant. The words, “anterior”, “posterior”, “superior,”“inferior,” “medial,” “lateral,” and related words and/or phrases areused to designate various positions and orientations in the human bodyto which reference is made. When these words are used in relation to theimplant 10 or a component thereof, they are to be understood asreferring to the relative positions of the implant 10 as implanted inthe body as shown in FIG. 1. The terminology includes the above-listedwords, derivatives thereof and words of similar import.

The implant 10 is described herein as extending horizontally along alongitudinal direction “L” and a transverse direction “T”, andvertically along a vertical direction “V”. The longitudinal direction Lcan be at least substantially perpendicular to each of the transverseand vertical directions T, V. The transverse direction T can be at leastsubstantially perpendicular to each of the longitudinal and verticaldirections L, V. The vertical direction V can be at least substantiallyperpendicular to each of the longitudinal and transverse directions L,T. Unless otherwise specified herein, the terms “longitudinal,”“transverse,” and “vertical” are used to describe the orthogonaldirectional components of various implant components and implantcomponent axes with reference to the orientation in which the implant 10is configured to be located in the intervertebral space 5; however, suchdirectional terms can be used consistently with reference to the implantregardless of its actual orientation. Additionally, it should beappreciated that while the longitudinal and transverse directions L, Vare illustrated as extending along and defining a horizontal plane (alsoreferred to herein as a “longitudinal-transverse plane”), and that thevertical direction is illustrated as extending along a vertical plane(such as either a “vertical-longitudinal plane” or a“vertical-transverse plane,” as respectively referred to herein), theplanes that encompass the various directions may differ during use. Forinstance, when the implant 10 is inserted into the intervertebral space5, the vertical direction V extends generally along thesuperior-inferior (or caudal-cranial) direction, the longitudinaldirection L extends generally along the medial-lateral direction, andthe transverse direction L extends generally along theanterior-posterior direction. Thus, the horizontal plane lies generallyin the anatomical plane defined by the anterior-posterior direction andthe medial-lateral direction. Accordingly, the directional terms“vertical”, “longitudinal”, “transverse”, and “horizontal” may be usedto describe the implant 10 and its components as illustrated merely forthe purposes of clarity and illustration, and such terms. With theforegoing in mind, the terms “expand” and “expansion,” when used inreference to the implant 10, refer to expansion along the verticaldirection V.

Referring now to FIG. 2, the implant 10 according to a first embodimentcan define a proximal end 12 and a distal end 14 spaced from one anotheralong the longitudinal direction L. In particular, the distal end 14 canbe spaced from the proximal end 12 in a distal direction and theproximal end 12 can be spaced from the distal end 14 in a proximaldirection opposite the distal direction. Thus, as used herein, the term“longitudinal direction L” is bi-directional and is defined by themono-directional distal and opposed proximal directions. Additionally,the implant 10 can define an anterior side 16 and a posterior side 18spaced from one another along the transverse direction T. In particular,the anterior side 16 can be spaced from the posterior side 18 in ananterior direction and the posterior side 18 can be spaced from theanterior side 16 in a posterior direction opposite the anteriordirection. Thus, as used herein, the term “transverse direction T” isbi-directional and is defined by the mono-directional anterior andopposed posterior directions.

The implant 10 can include a first or inferior plate 20 and a second orsuperior plate 22 spaced from each other along the vertical direction V.The inferior and superior plates 20, 22 may be referred to as“endplates.” The inferior plate 20 can define first or inferior platebody 24 and the superior plate 22 can define a second or superior platebody 26. The inferior plate body 24 can define a first or inferiorbone-contacting surface 28 on an exterior thereof. The superior platebody 26 can define a second or superior bone-contacting surface 30 on anexterior thereof, as shown in FIG. 3. The inferior and superiorbone-contacting surfaces 28, 30 can face away from one another. Inparticular, the superior bone-contacting surface 30 can face thesuperior vertebral surface 6 of the superior vertebra 2 and the inferiorbone-contacting surface 28 can face the inferior vertebral surface 8 ofthe inferior vertebral body 4. The inferior and superior bone-contactingsurfaces 28, 30 can each be substantially planar; however, in otherembodiments, each bone-contacting surface 28, 30 can be at leastpartially convex, for example, and can at least partially define atexture (not shown), such as spikes, ridges, cones, barbs, indentations,or knurls, which are configured to engage the respective vertebralbodies 2, 4 when the implant 10 is inserted into the intervertebralspace 5.

When the implant 10 is in the collapsed configuration, the inferior andsuperior bone-contacting surfaces 28, 30 can be spaced from one anotherby a distance D in the range of about 5 mm and about 20 mm along thevertical direction V, by way of non-limiting example, although othersizes are within the scope of the present disclosure. Additionally, whenthe implant 10 is in the collapsed configuration, the inferior andsuperior bone-contacting surfaces 28, 30 can be parallel with oneanother with respect to both the transverse direction T, and thus canhave a neutral (i.e., neither lordotic or kyphotic) collapsed profile.As used herein, the terms “lordosis”, “kyphosis”, and their respectivederivatives can be used interchangeably, with each term referring to anyconfiguration of the implant 10 wherein the inferior and superiorbone-contacting surfaces 28, 30 are angled with respect to each other inthe vertical-transverse plane.

It is to be appreciated that the inferior and superior plate bodies 24,26 can overly one another such that the proximal and distal ends 12, 14of the implant 10 can be characterized as the proximal and distal ends12, 14 of each plate 20, 22 or plate body 24, 26. Similarly, theanterior and posterior sides 16, 18 of the implant 10 can also becharacterized as the anterior and posterior sides 16, 18 of each plate20, 22 or plate body 24, 26.

As shown in FIGS. 2 and 3, the proximal end 12 of the implant 10 caninclude a coupling feature, such as a coupling aperture 32, forreceiving an insertion instrument configured to insert the implant 10into the intervertebral space. The coupling aperture 32 can becollectively defined by the inferior and superior plate bodies 24, 26.The implant 10 can also define one or more vertical apertures 34 (FIG.2) extending through the inferior and superior plate bodies 24, 26 alongthe vertical direction V. The vertical apertures 34 can be incommunication with one another and with the coupling aperture 32 and canbe configured to receive bone growth material following expansion of theimplant 10 for fusion with the superior and inferior vertebral bodies 2,4.

With continued reference to FIG. 2, the implant 10 can generally definean anterior portion 36 and a posterior portion 38 each elongated alongthe longitudinal direction L and located on opposite sides of thevertical apertures 34 with respect to the transverse direction T. Theimplant 10 can also generally define a distal portion 40 spaced from thevertical apertures 34 in the distal direction. The distal end 14 of theimplant 10 can also be termed the “insertion end” of the implant 10. Tofacilitate insertion, the superior and inferior plate bodies 12, 18 caneach define a tapered surface 42 adjacent the distal end 14, whereineach tapered surface 42 is declined in the distal direction, as shown inFIGS. 2 and 4.

Referring now to FIGS. 5 and 6, each of the inferior and superior platebodies 24, 26 can define an internal face 44 opposite the respectivebone-contacting surface 28, 30 with respect to the vertical direction V.Additionally, the internal faces 44 of the inferior and superior platebodies 24, 26 can each define one or more internal contact surfaces 46.When the implant 10 is in the collapsed configuration, the internalcontact surfaces 46 of the superior plate body 26 can abut the internalcontact surfaces 46 of the inferior plate body 24. The internal faces 44of the inferior and superior plate bodies 24, 26 can be coupled to, andconfigured to interface with, an expansion mechanism 48 that isconfigured to move expansion members, such as wedges 51, 52, 53, 54,with respect to one another in a manner expanding the implant 10 alongthe vertical direction V, as discussed in more detail below.

The internal face 44 of each plate body 24, 26 can also define ananterior channel 56 and a posterior channel 58 each elongated along thelongitudinal direction L. The anterior channel 56 and the posteriorchannel 58 of each plate 20, 22 can extend into the respective platebody 24, 26 from the internal contact surface 46 thereof toward therespective bone-contacting surface 28, 30 along the vertical directionV. The anterior channels 56 of the plates 12, 18 can be located withinthe anterior portion 36 of the implant 10, and the posterior channels 58of the plates 12, 18 can be located within the posterior portion 38 ofthe implant 10. The anterior channels 56 of the plates 12, 18 can overlyone another so as to at least partially define a first or anteriorcompartment 60 of the implant 10, while the posterior channels 58 of theplates 12, 18 can overly one another so as to at least partially definea second or posterior compartment 62 of the implant 10 (FIG. 3). Theanterior and posterior compartments 60, 62 can be configured to housecomponents of the expansion mechanism 48. Thus, the compartments 60, 62can be termed “expansion compartments.”

As shown more clearly in the enlarged view of FIG. 7, the anterior andposterior channels 56, 58 can each extend between opposed anterior andposterior sidewalls 64, 66 spaced apart along the transverse directionT. Each channel 56, 58 can also extend along the vertical direction Vfrom the internal contact surface 46 to a base surface 68 of the channel56, 58. Thus, the base surface 68 of each channel 56, 58 can becharacterized as being vertically recessed within the plate body 24, 26from the respective internal contact surface 46 toward the respectivebone-contacting surface 28, 30. The base surface 68 of each channel canextend along the longitudinal and transverse directions L, T, and canoptionally be substantially planar.

Each channel 56, 58 can also include a guide feature, such as a guideslot 70, that is recessed from the base surface 68 toward thebone-contacting surface 28, 30. Each guide slot 70 of the channels 56,58 can also be referred to as a “plate guide slot” 70. The plate guideslot 70 can have a geometry configured to guide movement of one or morecomponents of the expansion mechanism 48 within the channel 56, 58 alongthe longitudinal direction L. Optionally, the plate guide slot 70 canalso be configured to provide mechanical interference with suchcomponents in the vertical direction V toward to the internal contactsurface 46 of the associated plate 20, 22. Stated differently, the plateguide slot 70 can optionally have a geometry such that the plate body24, 26 interlocks with said component of the expansion mechanism 48 in amanner preventing decoupling of the component from the plate guide slot70 (and, by extension, from the channel 56, 58). Thus, the plate guideslot 70 can also be characterized as a retention feature. For example,the plate guide slot 70 can have a dovetail profile in thevertical-transverse plane, as shown. However, it is to be appreciatedthat other profiles and geometries of the plate guide slot 70 are withinthe scope of the present disclosure.

The internal faces 44 of the inferior and superior plate bodies 24, 26can also define one or more coupling features for coupling the inferiorand superior plate bodies 24, 26 together, particularly in the collapsedconfiguration. The coupling features of the plate bodies 14, 20 can beconfigured to nest within one another in a manner stabilizing theimplant 10 throughout various phases of operation. For example, as shownin FIGS. 5 and 6, at the distal portion 40 of the inferior plate body24, the internal face 44 can define a first transverse slot 72, a secondtransverse slot 74 spaced from the first transverse slot 72 in thedistal direction, and a transverse wall 76 positioned between the firstand second transverse slots 72, 74. The transverse wall 76 can extendalong the transverse direction T between an anterior wall end 78 and aposterior wall end 80.

As shown in FIG. 8, at the distal portion 40 of the superior plate body26, the inner face 44 can define a first transverse protrusion 82 and asecond transverse protrusion 84 spaced from the first transverseprotrusion 82 in the distal direction. Each of the first and secondtransverse protrusions 82, 84 can protrude from the superior plate body26 beyond the internal contact surfaces 46 thereof toward the inferiorplate body 24. The first and second transverse protrusions 82, 84 caneach extend along the transverse direction T between an anterior end 86and a posterior end 88, and can extend along the longitudinal directionL between a proximal face 90 and a distal face 92. When the implant 10is in the collapsed configuration, the first and second transverseprotrusions 82, 84 of the superior plate body 26 can nest within thefirst and second transverse slots 72, 74, respectively, of the inferiorplate body 24 (FIG. 4). As the implant 10 expands from the collapsedconfiguration, the transverse protrusions 82, 84 and transverse slots72, 74 can effectively stabilize the implant and inhibit relativemovement between the inferior and superior plate bodies 24, 26 along thelongitudinal direction L.

Referring again to FIGS. 5 and 6, the expansion mechanism 48 can bepositioned between the inferior and superior plates 20, 22. In theillustrated embodiment, the expansion mechanism 48 can be configured toconvert one or more rotational input forces applied by a physician intoone or more corresponding linear expansion forces along the verticaldirection V. The expansion mechanism 48 can include one or moreactuation assemblies 94, 96 each configured to convert a rotationalinput force into linear expansion forces along the vertical direction V.As shown, the expansion mechanism 48 can include a first or anterioractuation assembly 94 and a second or posterior actuation assembly 96spaced from each other along the transverse direction T. The anterioractuation assembly 94 can be configured to convert a first rotationalinput force R₁ into a plurality of linear expansion forces Z₁, Z₂, Z₃,Z₄, along the vertical direction V so as expand the anterior portion 36of the implant 10 along the vertical direction V. Similarly, theposterior actuation assembly 96 can be configured convert a secondrotational input force R₂ into a plurality of linear expansion forcesZ₁, Z₂, Z₃, Z₄, along the vertical direction V so as expand theposterior portion 38 of the implant 10 along the vertical direction V.

The anterior and posterior actuation assemblies 94, 96 can be driven soas to provide uniform or non-uniform expansion or contraction of theimplant 10 along the vertical direction, as desired by a physician. Forexample, either of the actuation assemblies 94, 96 can be drivenindependently of the other. When driven independently, the anterior andposterior actuation assemblies 94, 96 can expand the anterior andposterior portions 36, 38 of the implant 10 to different expandedheights along the vertical direction V, providing the implant 10 with alordotic profile in the intervertebral space 5, as discussed in moredetail below. Thus, the implant 10 allows vertical expansion within theintervertebral space and adjustment of the lordotic angle of the implant10 independently of one another.

The anterior and posterior actuation assemblies 94, 96 can be configuredsubstantially similarly; accordingly, the same reference numbers will beused herein with reference to the corresponding components and featuresof the actuation assemblies 94, 96. Each actuation assembly 94, 96 caninclude an actuator, such as a drive shaft 98, as also shown in FIG. 9.Each drive shaft 98 can define a central shaft axis X₁ that extendsalong the longitudinal direction L, and can also define a proximal end100 and a distal end 102 spaced from one another along the central shaftaxis X₁.

With continued reference to FIG. 9, the drive shaft 98 can include oneor more threaded portions 104, 106 configured to transmit one or morelinear drive forces F₁, F₂ along the longitudinal direction L. Forexample, the drive shaft 98 can include a first or proximal threadedportion 104 and a second or distal threaded portion 106 spaced from theproximal threaded portion 104 in the distal direction along the centralshaft axis X₁. The threading of the proximal and distal threadedportions 104, 106 can have different thread qualities. For example, inthe illustrated embodiment, the proximal threaded portion 104 defines athread pattern that is oriented in a direction opposite that of thedistal threaded portion 106. In this manner, upon rotation of the driveshaft 98, the proximal threaded portion 104 can provide a first lineardrive force F₁, the distal threaded portion 106 can provide a secondlinear drive force F₂, and the first and second linear drive forces F₁,F₂ can be opposite one another.

The drive shaft 98 can include an intermediate portion 108 positionedbetween the proximal and distal threaded portions 104, 106. Thethreading of the proximal threaded portion 104 can be substantiallycontiguous with the threading of the distal threaded portion 106 at theintermediate portion 108. Thus, the intermediate portion 108 can definea boundary between the threaded portions 104, 106. In the illustratedembodiment, the intermediate portion 108 can be characterized as aninternal end of each of the proximal and distal threaded portions 104,106, while the proximal end 100 of the drive shaft 98 can define theexternal end of the proximal threaded portion 104, and the distal end102 of the drive shaft 98 can define the external end of the distalthreaded portion 106. Furthermore, in the illustrated embodiment, theintermediate portions 108 of the anterior and posterior drive shafts 98can define a center or midpoint of the implant 10 with respect to thelongitudinal direction L. Thus, with respect to each threaded portion104, 106 of the drive shaft 98 (and any component positioned thereon),an external longitudinal direction L_(E) extends from the internal end108 to the external end 100, 102, and an internal longitudinal directionL_(I) extends from the external end 100, 102 to the internal end 108.

A head 110 can be located at the distal end 102 of the drive shaft 98and can be contiguous with the distal threaded portion 106. The head 110can be monolithic with the drive shaft 98 or can be a separatecomponent, such as a nut that is threadedly coupled to the distalthreaded portion 106. The head 110 can define a proximal end 112 and adistal end 114 spaced from the proximal end 112 along the longitudinaldirection L. A drive coupling, such as a nut socket 116, can bethreadedly coupled to the proximal end 100 of the drive shaft 98 and canbe contiguous with the proximal threaded portion 104. The nut socket 116can define a socket aperture 118 extending from a proximal end 120 ofthe nut socket 116 toward a distal end 122 thereof. The socket aperture118 can define a hex socket, as depicted, although other socketconfigurations can be employed for connection to a driving tool operatedby a physician.

Referring again to FIGS. 5 and 6, each actuation assembly 94, 96 caninclude one or more expansion assemblies 124, 126 (also referred to as“wedge assemblies”) that expand along the vertical direction V. Forexample, a first or proximal wedge assembly 124 can be engaged with theproximal threaded portion 104 of the drive shaft 98 and a second ordistal wedge assembly 126 can be engaged with the distal threadedportion 106 of the drive shaft 98. In FIG. 6, the proximal wedgeassembly 124 of the posterior actuation assembly 96 is identified indashed lines, while the distal wedge assembly 126 of the anterioractuation assembly 94 is identified in dashed lines. The proximal anddistal wedge assemblies 124, 126 can be characterized as sub-assembliesof the respective anterior and posterior actuation assemblies 94, 96.Additionally, within each actuation assembly 94, 96, the proximal anddistal wedge assemblies 124, 126 can optionally be substantial mirrorimages of one another about a vertical-transverse plane positioned atthe intermediate portion 108 of the drive shaft 98. Stated differently,the distal wedge assembly 126 can be configured virtually identical (orat least substantially similar) to the proximal wedge assembly 126, withthe primary difference being that the distal wedge assembly 126 isflipped with respect to the longitudinal direction L. Some minorvariations in the proximal and distal wedge assemblies 124, 126 will beset forth more fully below.

Each proximal and distal wedge assembly 124, 126 can include a pluralityof expansion members, or wedges 51, 52, 53, 54, that are movablerelative to each other so as to increase their collective height alongthe vertical direction V. For example, the expansion members can includea first wedge 51, a second wedge 52, a third wedge 53, and a fourthwedge 54. One or more of the wedges 51, 52, 53, 54 can engage therespective threaded portion 104, 106 of the drive shaft 98.

With reference to FIG. 4, when the implant 10 is in the collapsedconfiguration, the first wedge 51 can be positioned adjacent theexternal end of the respective threaded portion 104, 106 of the driveshaft 98; the second wedge 52 can be spaced from the first wedge 51 inthe internal longitudinal direction L_(I); the third wedge 53 can bespaced from the second wedge 52 in the internal longitudinal directionL_(I); and the fourth wedge 54 can be spaced from the third wedge 53 inthe internal longitudinal direction L_(I). Accordingly, the first wedge51 can be characterized as an “external-most” wedge, while the fourthwedge 54 can be characterized as an “internal-most” wedge, althoughother configurations are possible. Additionally, the wedges 51, 52, 53,54 can define geometries that provide each wedge assembly 124, 126 withtelescopic mobility in the longitudinal and vertical directions L, V.Stated differently, the wedges 51, 52, 53, 54 can be shaped such that,as the wedges 51, 52, 53, 54 engage one another, their collective heightcan increase while their collective length decreases, and vice versa, asset forth in more detail below.

Referring now to FIGS. 10 through 12, the first wedge 51 can have afirst wedge body 128 that defines an internal end 130 and an externalend 132 spaced from the internal end 130 along the longitudinaldirection L. The first wedge body 128 can also define anterior andposterior side surfaces 134, 136 spaced from each other along thetransverse direction T. The external end 132 of the first wedge body 128can define an external face 138 extending between an upward apex 140 anda bottom or base surface 142 of the body 128 along the verticaldirection V. The external face 138 can be substantially planar, althoughother geometries are within the scope of the present disclosure. Theexternal face 138 can be configured to abut another component of theimplant 10 in a manner limiting or preventing motion of the first wedgebody 128 in the external longitudinal direction L_(E) during operationof the implant 10 within a patient. For example, in the proximal wedgeassembly 124, the external face 138 of the first wedge 51 can beconfigured to abut the distal end 122 of the nut socket 116, by way ofnon-limiting example.

The upward apex 140 can be located at the external end 132 of the firstwedge body 128. The base surface 142 of the first wedge body 128 can beconfigured to engage the base surface 68 of the respective anterior orposterior channel 56, 58 of the inferior plate body 24. At least aportion of the base surface 142 of the first wedge body 128 can besubstantially planar and can be configured to translate at leastpartially across the base surface 68 of the respective channel 56, 58,for example, at least during assembly of the implant 10. In otherembodiments, once in place within the respective channel 56, 58, thefirst wedge 51 can be fixed to the inferior plate body 24, such as bywelding, brazing, adhesives, or mechanical fasteners. In furtherembodiments, the first wedge 51 can be monolithic with the inferiorplate body 24. As the first wedge 51 can be characterized as“supporting” the inferior plate body 24, the first wedge 51 can bereferred to herein as a “support member” or a “support wedge.”

In the illustrated embodiments, the first wedge 51 can also include afirst or inferior guide element, such as a guide protrusion 144, that isconfigured to translate within the plate guide slot 70 of the associatedchannel 56, 58 during assembly of the implant 10, for example. The guideprotrusion 144 can extend from the base surface 142 of the first guidebody 128. A bottom surface 146 of the guide protrusion 144 can define abottom-most portion of the first wedge 51 and of the respective wedgeassembly 124, 126. The guide protrusion 144 can have a geometry that isconfigured to guide movement of the first wedge body 128 within therespective channel 56, 58 along the longitudinal direction L.Additionally, the guide protrusion 144 of the first wedge body 128 andthe respective guide slot 70 of the inferior plate body 24 can becooperatively shaped so that the first wedge body 128 interlocks withthe inferior plate body 24 in a manner preventing the first wedge body128 and the inferior plate body 24 from detaching along the verticaldirection V. For example, the guide protrusion 144 and the plate guideslot 70 can have corresponding dovetail profiles in thevertical-transverse plane, as shown, although other geometries arewithin the scope of the present disclosure. In this manner, the firstwedge 51 can be longitudinally movable but substantially verticallyimmovable within the respective channel 56, 58 of the inferior platebody 24. Thus, the guide protrusion 144 can also be characterized as aretention feature of the first wedge 51. Additionally, the profiles ofthe guide protrusion 144 and of the plate guide slot 70 can allow thefirst wedge 51 and the inferior plate body 24 to be rotationallyinterlocked with one another so that, for example, the first wedge 51and the inferior plate body 24 can maintain the same angular positionabout the central shaft axis X₁ during expansion and optionally duringlordosis. In other embodiments, the rotational interlocking of the firstwedge 51 and the inferior plate body 24 can allow rotation of the firstwedge 51 about the central shaft axis X₁ to cause a substantiallysimilar degree of rotation of the inferior plate body 24 about thecentral shaft axis X₁, and vice versa.

The first wedge body 128 can also include an engagement elementconfigured to engage a portion of one or more other wedges of therespective wedge assembly 124, 126, such as the second wedge 52 and thefourth wedge 54, for example. The engagement element can include a firstinclined surface, or ramp 148, extending between the internal end 130and the upward apex 140 of the first wedge body 128. When positionedwithin the respective actuation assembly, 94, 96, the first wedge 51 canbe oriented so that the first ramp 148 is inclined in the externallongitudinal direction L_(E). In the illustrated embodiment, the firstramp 148 can be oriented at a first incline angle α₁ in a range of about10 degrees and about 60 degrees with respect to the longitudinaldirection L (FIG. 12). In other embodiments, the first incline angle α₁can be in the range of about 20 degrees and about 40 degrees withrespect to the longitudinal direction L. In further embodiments, thefirst incline angle α₁ can be in the range of about 25 degrees and about35 degrees with respect to the longitudinal direction L. In additionalembodiments, the first incline angle α₁ can be less than 10 degrees orgreater than 60 degrees with respect to the longitudinal direction L.

The first wedge body 128 can also define a second or superior guidefeature, such as a guide slot 150, configured to guide relative motionbetween the first wedge 51 and another wedge of the associated wedgeassembly 124, 126, such as the fourth wedge 54, for example. The guideslot 150 can be recessed into the first wedge body 128 from the firstramp 148. The guide slot 150 can extend from a guide slot opening 152 atthe internal end 130 of the first wedge body 128 to the external face138 of the first guide body 128 with respect to the longitudinaldirection L. The guide slot 150 can extend parallel with the first ramp148 and can have a geometry configured to guide movement therein of anassociated guide element of the fourth wedge 54. Optionally, the guideslot 150 can also be configured to interlock with the associated guideelement in a manner preventing the fourth wedge 54 from detaching fromthe first wedge 51, at least in a direction orthogonal to the first ramp148. As shown, the guide slot 150 can have a dovetail profile in thevertical-transverse plane, although other geometries are within thescope of the present disclosure. The guide slot 150 can traverse anentire length of the first ramp 148, as shown, or can optionallytraverse less than the entire length. Additionally, the guide slot 150can separate the first ramp 148 into anterior and posterior portions154, 156, which can be characterized as “rails.”

The first wedge body 128 can define a channel 158 extending through thebody 128 along the longitudinal direction L. The channel 158 can beU-shaped, and portions of the first wedge body 128 located on oppositetransverse sides of the channel 158 can be characterized as anterior andposterior arms 160, 162 of the first wedge body 128 (FIG. 10). Thechannel 158 can be sized, shaped, and/or otherwise configured to providespace for the respective threaded portion 104, 106 of the drive shaft 98to extend at least partially through the body 128 (i.e., between thearms 160, 162) without mechanically interfering with the body 128.Accordingly, the first wedge body 128 can have a U-shaped profile in avertical-transverse plane. The channel 158 can also intersect the guideslot 150 in a manner effectively dividing a portion of the guide slot150 into anterior and posterior slots 164, 166 defined in the anteriorand posterior arms 160, 162, respectively.

Referring now to FIGS. 13 through 15, a variation of the first wedge 51′is shown. In particular, the variant 51′ can be employed in theposterior actuation assembly 96. The variant 51′ can be substantiallysimilar to the first wedge 51 shown in FIGS. 10 through 12; thus, likereference numbers can be used, with the corresponding features of thevariant first wedge 51′ denoted with a “prime” notation. The primarydifference in the variant first wedge 51′ can be that the external face138′ of the first wedge body 128′ is a first external face 138′ that isdefined by a transversely external one of the anterior and posteriorarms 160′, 162′. Additionally, the opposite (i.e., transverselyinternal) one of the arms 160′, 162′ can define a second external face139′ that is recessed from the first external face 138′ in the internallongitudinal direction L_(I).

The first external face 138′ of the first wedge 51′ can abut theproximal side 112 of the head 110, and the second external face 139′ canabut the proximal face 90 of the first transverse protrusion 82 of thesuperior plate body 26 (FIG. 30). Thus, the proximal face 90 of thefirst transverse protrusion 82 can be termed an abutment surface of thesuperior plate body 26. Such a configuration can add stability to theimplant 10 at least during expansion, contraction, and/or lordoticangulation of the implant 10. In other embodiments, however, the firstwedge 51 of the distal wedge assembly 126 can be virtually identical tothe first wedge 51 of the proximal wedge assembly 124. As with the firstwedge 51, the variant 51′ can be characterized as a “support member” or“support wedge” and can optionally be rigidly fixed to the inferiorplate body 24 by welding, brazing, adhesives, or mechanical fasteners.It is to be appreciated that the variant first wedge 51′ of the anterioractuation assembly 94 can be a substantial mirror image of itscounterpart in the posterior actuation assembly 96 about avertical-longitudinal plane positioned between the actuation assemblies94, 96.

Referring now to FIGS. 16 through 18, the second wedge 52 can have asecond wedge body 168 that defines an internal end 170 and an externalend 172 spaced from the external end 172 along the longitudinaldirection L. The second wedge body 168 can also define anterior andposterior side surfaces 174, 176 spaced from each other along thetransverse direction T. The second wedge body 168 can also define anexternal face 178 at the external end 172. The external face 178 of thesecond wedge body 168 can extend along the vertical and transversedirections V, T and can be substantially planar, although othergeometries are within the scope of the present disclosure. The secondwedge body 168 can also define an upper base surface 180 and an opposeddownward apex 182 spaced from the upper base surface 180 along thevertical direction V. The upper base surface 180 can extend along thelongitudinal direction L between the internal and external ends 170, 172of the body 168. The downward apex 182 can be located between theexternal and internal ends 170, 172 of the second wedge body 168 withrespect to the longitudinal direction L.

The upper base surface 180 can be configured to engage the base surface68 of the respective anterior or posterior channel 56, 58 of thesuperior plate body 26. Accordingly, the second wedge 52 can becharacterized as “supporting” the superior plate body 26 and can bereferred to herein as a “support member” or “support wedge.” At least aportion of the upper base surface 180 can be substantially planar andcan be configured to translate at least partially across the basesurface 68 of the respective channel 56, 58 during expansion of theimplant 10. Thus, the second wedge 52 can also be referred to as a“slider.”

The second wedge body 168 can define a third or superior guide element,such as a guide protrusion 184, extending from the upper base surface180 along the vertical direction V. A top surface 186 of the guideprotrusion 184 can define a top-most portion of the second wedge 52. Thetop surface 186 can also define a top-most portion of the respectivewedge assembly 124, 126. The guide protrusion 184 can be configured totranslate within the guide slot 70 of the associated channel 56, 58 ofthe superior plate body 26. The guide protrusion 184 of the second wedgebody 168 can have a design and function generally similar to those ofthe guide protrusion 144 of the first wedge body 128 set forth above. Byway of non-limiting example, the guide protrusion 184 of the secondwedge body 168 and the guide slot 70 of the associated channel 56, 58 ofthe superior plate body 26 can have corresponding dovetail profiles thatinterlock the second wedge 52 to the superior plate body 26. In thismanner, guide protrusion 184 (which can also be characterized as a“retention” feature) can be longitudinally movable but substantiallyvertically immovable within the respective channel 56, 58 of thesuperior plate body 26. Additionally, the profiles of the guideprotrusion 184 and of the plate guide slot 70 can allow the second wedge52 and the superior plate body 26 to be rotationally interlocked withone another so that, for example, rotation of the second wedge 52 aboutthe central shaft axis X₁ of the drive shaft 98 causes a substantiallysimilar degree of rotation of the superior plate body 26 about thecentral shaft axis X₁, and vice versa.

The second wedge 52 can include one or more engagement elementsconfigured to engage portions of one or more of the other wedges of theassociated wedge assembly 124, 126. By way of non-limiting example, thesecond wedge body 168 can define a second inclined surface, or ramp 188,extending from the external face 178 to the downward apex 182, and athird inclined surface, or ramp 190, extending from the downward apex182 to the internal end 170 of the second wedge body 168. The internalend 170 of the second wedge body 168 can define a shared edge betweenthe upper base surface 180 and the third ramp 190. The second wedge 52can be oriented in each actuation assembly 94, 96 so that the secondramp 188 is inclined in the external longitudinal direction L_(E) andthe third ramp 190 is declined in the external longitudinal directionL_(E) (and thus inclined in the internal longitudinal direction L_(I)).The second ramp 188 can be configured to engage the first ramp 148 ofthe first wedge body 128 during expansion of the implant 10. The thirdramp 190 can be configured to engage a portion of another wedge of therespective wedge assembly 124, 126, such as the third wedge 53, forexample.

The second ramp 188 can optionally be substantially parallel with thefirst ramp 148 of the first wedge body 128. The second ramp 188 can beoriented at a second incline angle α₂ in a range of about 10 degrees andabout 60 degrees with respect to the longitudinal direction L (FIG. 18).In other embodiments, the second incline angle α₂ can be in the range ofabout 20 degrees and about 40 degrees with respect to the longitudinaldirection L. In further embodiments, the second incline angle α₂ can bein the range of about 25 degrees and about 35 degrees with respect tothe longitudinal direction L. In additional embodiments, the secondincline angle α₂ can be less than 10 degrees or greater than 60 degreeswith respect to the longitudinal direction L.

The third ramp 190 can be oriented at a third incline angle α₃ in therange of about 10 degrees and about 60 degrees with respect to thelongitudinal direction L. In other embodiments, the third incline angleα₃ can be in the range of about 20 degrees and about 40 degrees withrespect to the longitudinal direction L. In further embodiments, thethird incline angle α₃ can be in the range of about 25 degrees and about35 degrees with respect to the longitudinal direction L. In additionalembodiments, the third incline angle α₃ can be less than 10 degrees orgreater than 60 degrees with respect to the longitudinal direction L.

The second wedge 52 can include a fourth guide feature, such as a guideslot 192, configured to guide relative motion between the second wedge52 and another wedge of the associated wedge assembly 124, 126, such asthe third wedge 53, for example. The guide slot 192 can be recessed intothe second wedge body 168 from the third ramp 190 and can separate thethird ramp 190 into anterior and posterior portions 194, 196, which canbe characterized as “rails.” The guide slot 192 can extend parallel withthe third ramp 190 and can have a geometry configured to guide movementof, and optionally interlock with, an associated guide element of thethird wedge 53. As shown, the guide slot 192 can have a dovetailprofile, and can be configured similarly to the guide slot 150 of thefirst wedge body 128, as set forth above, although other geometries arewithin the scope of the present disclosure. The guide slot 192 canextend from a guide slot opening 198 at the upper base surface 180 to astop feature 200 configured to prevent the guide element of the thirdwedge 53 from moving beyond the stop feature 200 along the externallongitudinal direction L_(E). The stop feature 200 can be spaced fromthe downward apex 182 in the internal longitudinal direction L_(I).Thus, the guide slot 192 can extend less than an entire length of thethird ramp 190.

The second wedge body 168 can define a channel 202 extendingtherethrough along the longitudinal direction L. The channel 202 of thesecond wedge body 168 can be configured similarly to the channel 158 ofthe first wedge body 128 set forth above. Thus, the second wedge body168 can have a U-shaped profile in a vertical-transverse plane and caninclude anterior and posterior arms 204, 206 on opposite transversesides of the channel 202. Additionally, the channel 202 can separate thesecond ramp 188 into anterior and posterior portions 208, 210, which canbe characterized as “rails.” The channel 202 can also intersect theguide slot 192 in a manner effectively converting a portion of the guideslot 192 into anterior and posterior slots 212, 214 defined in theanterior and posterior arms 204, 206, respectively.

Referring now to FIGS. 19 through 21, the third wedge 53 can have athird wedge body 216 that defines an internal end 218 and an externalend 220 spaced from the internal end 218 along the longitudinaldirection L. The third wedge body 216 can also define anterior andposterior side surfaces 222, 224 spaced from each other along thetransverse direction T. The third wedge body 216 can also define aninternal face 226 at the internal end 218 thereof and an external face228 at the external end 220. The internal and external faces 226, 228 ofthe third wedge body 216 can each extend along the vertical andtransverse directions V, T and can each be substantially planar,although other geometries are within the scope of the presentdisclosure. The third wedge body 216 can define a central bore 230extending along a central bore axis X₂. The central bore 230 can be athrough bore, and the central bore axis X₂ can extend along thelongitudinal direction L. The central bore 230 can define threading 232that is configured to engage at least one of the proximal and distalthreaded portions 104, 106 of the drive shaft 98 so that rotation of thedrive shaft 98 threadedly translates the third wedge 53 along thelongitudinal direction L. Accordingly, the central bore axis X₂ can becoextensive with the central shaft axis X₁. The third wedge body 216 canalso be configured to rotate about the central bore axis X₂, as setforth in more detail below.

The third wedge 53 can include one or more engagement elementsconfigured to engage portions of one or more of the other wedges of theassociated wedge assembly 124, 126, such as the second and fourth wedges52, 54. For example, the internal face 226 of the third wedge 53 can beconfigured to engage (such as by abutting) a portion of the fourth wedge54. Additionally, the third wedge body 216 can define a fourth inclinedsurface, or ramp 234, located at an upper side of the body 216. Thefourth ramp 234 can extend between the internal and external faces 226,228 along the longitudinal direction L. The fourth ramp 234 can bedeclined in the external longitudinal direction L_(E) (and thus inclinedin the internal longitudinal direction L_(I)).

The fourth ramp 234 can be configured to engage the third ramp 188 ofthe second wedge body 168, including during expansion of the implant 10.The fourth ramp 234 can optionally be substantially parallel with thethird ramp 190 of the second wedge body 168. The fourth ramp 234 can beoriented at a fourth incline angle α₄ in a range of about 10 degrees andabout 60 degrees with respect to the longitudinal direction L (FIG. 21).In other embodiments, the fourth incline angle α₄ can be in the range ofabout 20 degrees and about 40 degrees with respect to the longitudinaldirection L. In further embodiments, the fourth incline angle α₄ can bein the range of about 25 degrees and about 35 degrees with respect tothe longitudinal direction L. In additional embodiments, the fourthincline angle α₄ can be less than 10 degrees or greater than 60 degreeswith respect to the longitudinal direction L.

The third wedge 53 can include a fifth guide element, such as a guideprotrusion 236, configured to guide motion between the third wedge 53and the second wedge 52. For example, the guide protrusion 236 of thethird wedge 53 can extend vertically from the fourth ramp 234 and can beconfigured to translate within the guide slot 192 of the second wedge52. The guide protrusion 236 can be cooperatively shaped with the guideslot 192 in a manner preventing the guide protrusion 236 from exitingthe guide slot 192, at least in a direction orthogonal to the third ramp190. For example, the guide protrusion 236 and the guide slot 192 canhave corresponding dovetail profiles in a vertical-transverse plane, asshown. In such an embodiment, the guide protrusion 236 can only enterand exit the guide slot 192 through the guide slot opening 198.Additionally, the profiles of the guide slot 192 and the guideprotrusion 236 can allow the second and third wedges 52, 53 to berotationally interlocked with one another so that, for example, rotationof the third wedge 53 about the central bore axis X₂ causes asubstantially similar degree of rotation of the second wedge 52 aboutthe central bore axis X₂.

The third wedge 53 can have a geometry configured to avoid contact withthe first wedge 51 during relative movement between the first and thirdwedges 51, 53. For example, the third wedge body 216 can have a roundedunderside 238 configured so as not to contact or otherwise directlyengage or interfere with the first ramp 148 or the anterior andposterior arms 160, 162 of the first wedge body 128 during translationaland rotational movement of the third wedge body 216 over the first wedgebody 128. Additionally, the underside 238 can define a fifth inclinedsurface, or ramp 240, that is oriented at a fifth incline angle α₅ thatis substantially parallel with the first incline angle α₁ of the firstramp 148. The fifth ramp 240 can be configured so as not to contact thefirst ramp 148. For example, the fifth ramp 240 can include a pair ofplanar portions 242 positioned on opposite transverse sides of a roundedportion 244. The rounded portion 244 can be configured to extend withinthe guide slot 150 of the first wedge body 128 without contacting thefirst ramp 148 or any other portion of the first wedge body 128 duringtranslational and rotational movement of the third wedge body 216 overthe first wedge body 128. Additionally, the planar portions 242 of thefifth ramp 240 can be remote from the first ramp 148 or any otherportion of the first wedge body 128 during movement of the third wedgebody 216 over the first wedge body 128.

Referring now to FIGS. 22 through 25, the fourth wedge 54 can have afourth wedge body 246 that defines an internal end 248 and an externalend 250 spaced from the internal end 248 along the longitudinaldirection L. The fourth wedge body 246 can also define anterior andposterior side surfaces 252, 254 spaced from each other along thetransverse direction T. The fourth wedge body 246 can also define aninternal face 256 at the internal end 248 thereof and an external face258 at the external end 250. The internal and external faces 256, 258 ofthe fourth wedge body 246 can each extend along the vertical andtransverse directions V, T and can each be substantially planar,although other geometries are within the scope of the presentdisclosure. The fourth wedge body 246 can include a top surface 260 anda bottom surface 262 opposite the top surface 260 with respect to thevertical direction V. The bottom surface 262 can also be referred to asa “base” surface of the fourth wedge 54, and can extend along thelongitudinal and transverse directions L, T. The bottom surface 262 canoptionally be planar. The fourth wedge body 246 can be rounded orchamfered between the top surface 260 and the side surfaces 252, 254 soas to avoid contacting or otherwise directly engaging or interferingwith the third ramp 190 or any other portion of the second wedge body168 during translational and rotational movement of the fourth wedgebody 246 under the second wedge body 168, for example.

The fourth wedge body 246 can define a central bore 264 extending alonga central bore axis X₃. The central bore 264 can be a through bore andcan extend along the longitudinal direction L. The central bore axis X₃of the fourth wedge body 246 can be coextensive with the central shaftaxis X₁ of the drive shaft 98 and with the central bore axis X₂ of thethird wedge body 216. The central bore 264 of the fourth wedge body 246can define threading 266 that is configured to engage the same one ofthe proximal and distal threaded portions 104, 106 as the threading 232of the third wedge body 216. In the illustrated embodiments, rotation ofthe drive shaft 98 can threadedly translate the third and fourth wedges53, 54 together along the longitudinal direction L at the same rate.However, in other embodiments, the third and fourth wedges 53, 54 ofeach wedge assembly 124, 126 can move at different rates and/or inopposite directions along the drive shaft 98.

The fourth wedge 54 can include one or more engagement elementsconfigured to engage portions of at least one of the other wedges of theassociated wedge assembly 124, 126, such as the third wedge 53. Forexample, the external face 258 of the fourth wedge body 246 can becharacterized as an engagement element because it can be configured toabut the internal face 226 of the third wedge body 216. The externalface 258 of the fourth wedge body 54 can optionally be configured toabut the internal face 226 of the third wedge body 216 in a mannerensuring that the third and fourth wedge bodies 216, 158 translate alongthe respective threaded portion 104, 106 of the drive shaft 98 at thesame rate. In this manner, the fourth wedge 54 can be characterized as a“pusher” or a “pusher member” that effectively pushes the third wedge 53in the external longitudinal direction L_(E). Additionally, it is to beappreciated that the third and fourth wedges 53, 54 can collectively bereferred to as an “expansion wedge”, with the third wedge 53 beingreferred to as a “first member” or “first portion” of the expansionwedge, and the fourth wedge 54 being referred to as a “second member” or“second portion” of the expansion wedge. Additionally, each of the thirdand fourth wedges 53, 54 can be referred to individually as an“expansion wedge.”

The fourth wedge body 246 can also define a sixth inclined surface, orramp 268, adjacent the bottom surface 262 of the body 246. The sixthramp 268 can extend between the bottom surface 262 and the external face256 of the fourth wedge body 246 with respect to the longitudinaldirection L. The sixth ramp 268 can be inclined in the externallongitudinal direction L_(E) (and thus declined in the internallongitudinal direction L_(I)). The sixth ramp 268 can be configured toengage the first ramp 148 of the first wedge body 128 during expansionof the implant 10. The sixth ramp 268 can optionally be substantiallyparallel with the first ramp 148. The sixth ramp 268 can be oriented ata sixth incline angle α₆ in a range of about 10 degrees and about 60degrees with respect to the longitudinal direction L (FIG. 24). In otherembodiments, the sixth incline angle α₆ can be in the range of about 20degrees and about 40 degrees with respect to the longitudinal directionL. In further embodiments, the sixth incline angle α₆ can be in therange of about 25 degrees and about 35 degrees with respect to thelongitudinal direction L. In additional embodiments, the sixth inclineangle α₆ can be less than 10 degrees or greater than 60 degrees withrespect to the longitudinal direction L.

The fourth wedge 54 can include a sixth guide element, such as a guideprotrusion 270, configured to guide motion between the fourth wedge 54and each of the inferior plate 12 and the first wedge 51. The guideprotrusion 270 can extend from each of the bottom surface 262 and thesixth ramp 268. The guide protrusion 270 can be configured such that, inone phase of expansion of the implant 10, the protrusion 270 cantranslate within the guide slot 70 of the respective channel 68 of theinferior plate body 24 and, during another phase of expansion, theprotrusion 270 can translate within the guide slot 150 of the firstwedge 51.

The guide protrusion 270 of the fourth wedge body 246 can include one ormore portions configured to selectively engage guide features of theinferior plate body 24 and guide features of the first wedge 51. Forexample, in the non-limiting example shown in FIGS. 22 through 24, theguide protrusion 270 can include a first portion 271, a second portion272, a third portion 273, and a fourth portion 274. The first portion271 can extend from the sixth ramp 268. The fourth portion 274 canextend from the bottom surface 262. The second portion 272 can belocated underneath the first portion 271. The third portion 273 can begenerally underneath the fourth portion 274. The first and fourthportions 271, 274 can each have a rectangular profile in thevertical-transverse plane. The second and third portions 272, 273 caneach have a dovetail profile in the vertical-transverse plane. On eachof the anterior and posterior sides 252, 254 of the fourth wedge body246, an edge 276 between the first and second portions 271, 272 can beparallel with the bottom surface 262. Also on each side 252, 254, anedge 278 between the third and fourth portions 273, 274 can be parallelwith the sixth ramp 268. The second portion 272 can taper transverselyinward toward the first portion 271 from an edge 280 between the secondand third portions 272, 273. The third portion 273 can tapertransversely inward toward the fourth portion 274 from the edge 280between the second and third portions 272, 273.

As shown in FIG. 26, during a first phase of expansion of the implant10, the second, third and fourth portions 272, 273, 274 of the guideprotrusion 270 of the fourth wedge 54 can be positioned within therespective plate guide slot 70 while the first portion 271 is positionedexternal of the plate guide slot 70. As shown in FIG. 27, at theconclusion of the first phase, which can also be considered thecommencement of a second phase of expansion, the protrusion 270 can besimultaneously positioned in both the plate guide slot 70 and the guideslot 150 of the first wedge 51. The geometry of the protrusion 270allows it to transition from the plate guide slot 70 to the first wedgeguide slot 150, and to remain within the first wedge guide slot 150during the second phase of expansion, as shown in FIG. 28. During thesecond phase, the first, second, and third portions 271, 272, 273 of theguide protrusion 270 can be positioned within the guide slot 150 of thefirst wedge 51 while the fourth portion 274 can be external of the guideslot 150.

It is to be appreciated that the dovetail profile of the guideprotrusion 270, particularly at the edge 280 between the second andthird portions 272, 273, can substantially match the dovetail profilesof the guide slots 70 of each channel 62, 64 as well as the guide slot102 of the first wedge 51. The second portion 272 of the guideprotrusion 270 can be configured to allow the guide protrusion 270 totransfer from the guide slot 70 of the inferior plate body 24 to theguide slot 150 of the first wedge 51 between the first and secondphases. The third portion 273 of the guide protrusion 270 can beconfigured to allow the guide protrusion 270 to transfer from the guideslot 150 of the first wedge 51 to the guide slot 70 of the inferiorplate body 24 during an optional reverse expansion process (i.e., duringa collapsing or “contracting” process) of the implant 10, as set forthin more detail below.

The third portion 273 of the guide protrusion 270, particularly at theedge 280 between the second and third portions 272, 273, can becooperatively shaped with the guide slot 150 of the first wedge 51 in amanner preventing the guide protrusion 270 from exiting the guide slot150, at least in a direction orthogonal to the first ramp 148 andoptionally in any direction except a direction parallel with the firstramp 148. In the illustrated embodiment, the guide protrusion 270 canenter and exit the guide slot 150 only at the internal end 130 (throughthe guide slot opening 198) or optionally at the external end 132 of thefirst wedge body 128.

Additionally, the second portion 272 of the guide protrusion 270,particularly at the edge 280 between the second and third portions 272,273, can be cooperatively shaped with the guide slot 70 of therespective channel 62, 64 of the inferior plate body 24 in a mannerpreventing the guide protrusion 270 from exiting the guide slot 70, atleast in a direction orthogonal to the channel base surface 68 andoptionally in any direction except the longitudinal direction L or adirection parallel with the first ramp 148. Additionally, the profilesof the guide protrusion 270 and of the plate guide slot 70 can allow theinferior plate body 24 to be rotationally interlocked with the fourthwedge 54 when the guide protrusion 270 is within the plate guide slot 70(FIG. 26) so that, for example, the fourth wedge 54 and the inferiorplate body 24 can maintain the same angular position about the centralshaft axis X₁. Because the first wedge 51 can be rotationallyinterlocked with the inferior plate body 24 (FIG. 40), and the fourthwedge 54 can be rotationally interlocked with either the inferior platebody 24 or with the first wedge 51 (FIGS. 26 through 28), the inferiorplate body 24 can thus be rotationally interlocked with both of thefirst and fourth wedges 51, 54 during all phases of expansion.

It is to be appreciated that, in the illustrated embodiment, the second,third and fourth wedges 52, 53, 54 of the proximal wedge assembly 124can be substantially similar, or even virtually identical, to theirrespective counterparts in the distal wedge assembly 126. However, inother embodiments, one or more of the second, third and fourth wedges52, 53, 54 of the proximal wedge assembly 124 can be configureddifferently than their respective counterparts in the distal wedgeassembly 126.

Referring now to FIG. 29, a distal wedge assembly 126 is illustratedduring the second phase of expansion. The profiles of the guide slot 192of the second wedge 52 and the guide protrusion 236 of the third wedgecan allow the second wedge 52 to be rotationally interlocked with thethird wedge 53 as the third wedge 53 rotates relative to the fourthwedge 54 about the axis X₁ of the drive shaft 98, as set forth above.Additionally, as also set forth above, the profiles of the guide slot150 of the first wedge 51 and the guide protrusion 270 of the fourthwedge 54 can allow the first and fourth wedges 51, 54 to be rotationallyinterlocked with one another when the guide protrusion 270 is within theguide slot 150 so that, for example, the first and fourth wedges 51, 54maintain the same angular position about the central shaft axis X₁ or,in other embodiments, so that the first and fourth wedges 51, 54 rotateby the same degree about the central shaft axis X₁ during operation ofthe implant 10.

Referring now to FIG. 30, the wedges 51, 52, 53, 54 of each wedgeassembly 124, 126 can have telescopic mobility in the longitudinal andvertical directions L, V. It is to be appreciated that, when the implant10 is in the collapsed configuration, each of the anterior and posterioractuation assemblies 94, 96, and each of the proximal and distal wedgeassemblies 124, 126 can also be considered as being in its respectivecollapsed configuration. For purposes of comparison, FIG. 30 depicts theproximal wedge assembly 124 in the collapsed configuration while thedistal wedge assembly 124 is depicted in the fully expandedconfiguration. Each wedge assembly 124, 126 can define a length,measured from the external face 138 of the first wedge 51 to theinternal face 256 of the fourth wedge 54 along the longitudinaldirection L, and a height, measured from the bottom surface 146 of theguide protrusion 144 of the first wedge 51 to the top surface 186 of theguide protrusion 184 of the second wedge 122 along the verticaldirection V. In the collapsed configuration, each wedge assembly 124,126 can define a collapsed length L₁ and a collapsed height H₁. In thefully expanded configuration, each wedge assembly 124, 126 can define anexpanded length L₂ that is less than the collapsed length L₁, and anexpanded height H₂ that is greater than the collapsed height H₁. Stateddifferently, each wedge assembly 124, 126 can decrease in length as itincreases in height. The ratio of the expanded height H₂ to thecollapsed height H₁ can be in the range of about 1.5:1 to 3.5:1, by wayof non-limiting example. Accordingly, the vertical distance D betweenthe bone-contacting surfaces 28, 30 (FIG. 31) can also increase by asimilar margin during expansion of the implant 10. For example, thevertical distance D can increase by a factor in the range of about 1.05and about 3.0 from the collapsed configuration to the fully expandedconfiguration, by way of non-limiting example.

Operation of the implant 10, including expansion and lordosis, will nowbe discussed with reference to FIGS. 31 through 41, beginning with theimplant in the collapsed configuration, as shown in FIG. 31.

Referring now to FIG. 31, while the posterior actuation assembly 96 isdepicted, it is to be appreciated that the following description canalso apply to the corresponding components of the anterior actuationassembly 94. When the implant 10 is in the collapsed configuration, theinternal contact surfaces 46 of the inferior and superior plate bodies24, 26 can abut one another. Additionally, when collapsed, eachactuation assembly 94, 96 can be disposed substantially entirely withinthe associated compartment 60, 62 (FIG. 2) defined by the overlyingchannels 56, 58 of the plates 12, 18. The proximal end 120 of the nutsocket 116 can be generally aligned with the proximal end 12 of theimplant 10 along the transverse direction T. The drive shaft 98 canextend along the longitudinal direction L through the channels 56, 58.One or both of the distal end 114 of the head 110 and the distal end 102of the drive shaft 98 can abut or be adjacent to the proximal face 90 ofthe second transverse protrusion 84 of the superior plate body 26. Theproximal end 112 of the head 110 can abut or be adjacent to the distalface 92 of the first transverse protrusion 82 of the superior plate body26. In this manner, the head 110 can be aligned with the transverse wall76 of the inferior plate body 24 along the transverse direction T.

With reference to the proximal wedge assembly 124 in the collapsedconfiguration, the external face 138 of the first wedge 51 can abut orbe adjacent to the distal end 122 of the nut socket 116. The bottom basesurface 142 of the first wedge 51 can abut the base surface 68 of theposterior channel 58 of the inferior plate body 24 and the guideprotrusion 144 of the first wedge 51 can be received within the guideslot 70 of the posterior channel 58 of the inferior plate body 24. Theproximal threaded portion 104 of the drive shaft 98 can extend throughthe U-shaped channel 158 of the first wedge 51.

The second wedge 52 can be positioned such that the second ramp 188abuts the first ramp 148 at a location adjacent the internal end 130 ofthe first wedge 51. The upper base surface 180 of the second wedge 52can abut the base surface 68 of the posterior channel 58 of the superiorplate body 26 and the guide protrusion 184 of the second wedge 52 can bereceived within the guide slot 70 of the posterior channel 58 of thesuperior plate body 26. The proximal threaded portion 104 of the driveshaft 98 can extend through the U-shaped channel 202 of the second wedge52.

The third wedge 53 can be positioned such that the fourth ramp 234thereof abuts the third ramp 190 of the second wedge 52 at a locationadjacent the internal end 170 thereof. The guide protrusion 236 of thethird wedge 53 can be received within the guide slot 192 of the secondwedge 52. The drive shaft 98 can extend through the central bore 230 ofthe third wedge 53, with the threading 232 thereof engaged with theproximal threaded portion 104 of the drive shaft 98.

The fourth wedge 54 can be positioned such that the external face 258thereof abuts or is adjacent to the internal face 226 of the third wedge53. The internal face 256 of the fourth wedge 54 can be positioned at oradjacent the intermediate portion 108 of the drive shaft 98 (i.e., theinternal end of the proximal threaded portion 104). The bottom surface262 of the fourth wedge 54 can abut the base surface 68 of the posteriorchannel 58 of the inferior plate body 24 and the guide protrusion 270 ofthe fourth wedge 54 can be received within the guide slot 70 of theposterior channel 58 of the inferior plate body 24. The drive shaft 98can extend through the central bore 264 of the fourth wedge 53, with thethreading 266 thereof engaged with the proximal threaded portion 104 ofthe drive shaft 98.

It is to be appreciated that, as set forth above, the distal wedgeassembly 126 can effectively be a substantial mirror image of theproximal wedge assembly 124 about a vertical-transverse plane positionedat the intermediate portion 108 of the drive shaft 98. Thus, therelative positions of the wedges 51′, 52, 53, 54 of the distal wedgeassembly 126 and the distal threaded portion 106 of the drive shaft 98can be substantially similar to that of the proximal wedge assembly 124and the proximal threaded portion 104 of the drive shaft. With regardsto the variant of the first wedge 51′, the first external face 138′thereof can abut or be adjacent the proximal end 112 of the head 110(FIG. 5) while the second external face 139′ of the first wedge 51′ canabut or be adjacent to the proximal face 90 of the first transverseprotrusion 82 of the superior plate body 26 (FIG. 4).

Expansion of the implant 10 between the collapsed configuration and afirst partially expanded configuration, as shown in FIGS. 32 through 34,will now be discussed, according to an example mode of expansion. It isto be appreciated that, while FIGS. 32 through 34 depict the anteriorand posterior actuation assemblies 94, 96 actuated concurrently so as toexpand the implant 10 uniformly, each of the anterior and posterioractuation assemblies 94, 96 can be operated independently to providenon-uniform expansion or contraction of the implant 10 (i.e., lordosis).

During a first phase of expansion, the drive shaft 98 can be rotatedabout its central shaft axis X₁ in a first rotational direction (such asclockwise, for example) so that the proximal threaded portion 104provides a first or proximal drive force F₁ in the external longitudinaldirection L_(E) thereof (i.e., the proximal direction) and the distalthreaded portion 106 provides a second or distal drive force F₂ in theexternal longitudinal direction L_(E) thereof (i.e., the distaldirection). The threading 232, 178 of the central bores 146, 176 of thethird and fourth wedges 53, 54, respectively, can engage the associatedthreaded portion 104, 106 of the drive shaft 98 in a manner transmittingthe respective drive force F₁, F₂ to the third and fourth wedges 53, 54causing the third and fourth wedges 53, 54 to translate in the externallongitudinal direction L_(E).

Referring to FIG. 34, as the third and fourth wedges 53, 54 translate,each of the following can occur: the bottom surface 262 of the fourthwedge 54 rides along the base surface 68 of the respective anteriorchannel 56, 58 of the inferior plate 20; the guide protrusion 270 of thefourth wedge 54 rides within the guide slot 70 of the respective channel56, 58; the fourth ramp 234 of the third wedge 53 rides along the thirdramp 190 of the second wedge 52; and the guide protrusion 236 of thethird wedge 53 rides within the guide slot 192 of the second wedge 52.The vertical distance D between the inferior and superiorbone-contacting surfaces 28, 30 can increase by a factor in the range ofabout 0.2 and about 1.0 as a result of the fourth ramp 234 riding alongthe third ramp 190. As the fourth ramp 234 rides along the third ramp190, the first drive force F₁ can be conveyed at least to the secondwedge 52 causing the second ramp 188 (not visible in FIG. 34) to ridealong the first ramp 148 of the first wedge 51, further increasing thedistance D between the bone-contacting surfaces 28, 30 along thevertical direction V by a factor in the range of about 0.2 to 1.0 (withrespect to the collapsed distance D).

As the fourth ramp 234 rides along the third ramp 190 and as the secondramp 188 rides along the first ramp 148, the sixth ramp 268 of thefourth wedge 54 can approach the first ramp 148 of the first wedge 51.In the present example, the first phase of expansion can be completewhen the sixth ramp 268 abuts the first ramp 148, at which point theprotrusion 270 of the fourth wedge 54 can enter the opening 152 of theguide slot 150 of the first wedge 51 (FIG. 28). As set forth above, thegeometry of the guide protrusion 270 of the fourth wedge 54 can allowthe protrusion 270 to be simultaneously positioned within the plateguide slot 70 and the guide slot 150 of the first wedge 51 at theconclusion of the first phase of expansion (and at the commencement ofthe second phase of expansion).

At the conclusion of the first phase and commencement of the secondphase of expansion, the external end 172 of the second wedge 52, as wellas the entire second ramp 188, can be positioned intermediate theinternal and external ends 130, 132 of the first wedge 51 with respectto the longitudinal direction L. Moreover, the entire fourth ramp 234can be positioned intermediate the downward apex 182 and the internalend 170 of the second wedge 52, while the protrusion 236 of the thirdwedge 53 can be positioned intermediate the stop feature 200 and theopening 198 of the guide slot 192 of the second wedge 52, each withrespect to the longitudinal direction L. It is to be appreciated that,while views of the internal end 90 of the first wedge 51 and thedownward apex 182 and stop feature 200 of the second wedge 52 are eachobstructed in FIG. 34, such features are visible in FIG. 31.

Expansion of the implant 10 between the first partially expandedconfiguration, as shown in FIGS. 32 through 34, and a fully expandedconfiguration, as shown in FIGS. 35 through 37, will now be discussed,according to the example mode of expansion.

Referring now to FIGS. 35 through 37, the implant 10 is shown uniformlyexpanded at the conclusion of the second phase of expansion, which canbe commensurate with the fully expanded configuration. As above, it isto be appreciated that the anterior and posterior actuation assemblies94, 96 can each be operated independently to provide non-uniformexpansion or contraction of the implant 10 (i.e., lordosis) between thefirst partially expanded configuration and the fully expandedconfiguration.

Referring to FIGS. 35 through 37, during the second phase of expansion,the drive shaft 98 can be further rotated about its central shaft axisX₁ in the first rotational direction. The threading 232, 178 of thethird and fourth wedges 53, 54, respectively, can continue to engage theassociated threaded portion 104, 106 of the drive shaft 98 in a mannertranslating the third and fourth wedges 53, 54 further in the externallongitudinal direction L_(E). The second phase of expansion can becharacterized as when the sixth ramp 268 rides along the first ramp 148,which yet further increases the distance D between the inferior andsuperior bone-contacting surfaces 28, 30.

As the fourth wedge 54 translates at the commencement of the secondphase of expansion, the protrusion 270 can transition from the guideslot 70 of the channel 56, 58 of the inferior plate body 24 to the guideslot 150 of the first wedge 51. In particular, the geometry of thefirst, second, third and fourth portions 271, 272, 273, 274 of theprotrusion 270 can engage the guide slot 150 of the first wedge 51 sothat the protrusion 270 is caused to exit the plate guide slot 70 and tobe received entirely within the guide slot 150 of the first wedge 51.Additionally, the fifth ramp 240 of the third wedge 53 can extend withinthe guide slot 150 of the first wedge 51 without contacting the firstwedge body 128.

During at least a portion of the second phase of expansion, the sixthramp 268 can ride along the first ramp 148 while the fourth ramp 234rides along the third ramp 190, resulting in relative motion between thesecond wedge 52 and each of the third and fourth wedges 53, 54 along thelongitudinal and vertical direction L, V. Such relative motion betweenthe second wedge 52 and the third and fourth wedges 53, 54 during thesecond phase can cause the second ramp 188 to separate from, orotherwise become remote from, the first ramp 148 with respect to thevertical direction V. Additionally, such relative motion between thesecond wedge 52 and the third and fourth wedges 53, 54 can be initiatedby a reactionary force imparted to at least one of the second, third,and fourth wedges 52, 53, 54. For example, the reactionary force canoccur when a component of the implant 10, such as a stop feature in thechannel 56, 58, the guide slot 70, or other portion of the plate body24, 26, impedes motion of the second wedge 52 in the externallongitudinal direction L_(E). In another non-limiting example, thesecond and sixth ramps 124, 180 can ride along the first ramp 148 at ornear the same rate until, in the proximal wedge assembly 124, theexternal face 178 of the second wedge 52 abuts the distal end 122 of thenut socket 116 while, in the distal wedge assembly 126, the externalface 178 of second wedge 52 abuts the proximal face 90 of the firsttransverse protrusion 82. In each of the proximal and distal wedgeassemblies 124, 126, the foregoing abutments can impede further movementof the second wedge 52 along the external longitudinal direction L_(E)while the fourth ramp 234 continues to ride along the third ramp 190 andthe sixth ramp 268 continues to ride along the first ramp 148, thusdriving the second wedge 52 upward with respect to the first wedge 51.

In another non-liming example, the reactionary force can occur at thecommencement of the second phase of expansion, causing the fourth ramp234 to ride along the third ramp 190 as soon as the sixth ramp 268 ridesalong the first ramp 148. In such an example, in each of the proximaland distal wedge assemblies 124, 126, the fourth ramp 234 can ride alongthe third ramp 190 until the guide protrusion 236 of the third wedge 53abuts the stop feature 200 of the guide slot 192 of the second wedge 52,after which the sixth ramp 268 can continue to ride along the first ramp148 without any relative motion between the second wedge 52 and thethird and fourth wedges 53, 54 along the longitudinal and verticaldirections L, V. Thus, in each of the two preceding non-limitingexamples, the second phase of expansion can include at least one portionor sub-phase that involves relative motion between the second wedge 52and each of the third and fourth wedges 53, 54 with respect to thelongitudinal and vertical directions L, V, and at least one otherportion or sub-phase during which the second, third, and fourth wedges52, 53, 54 are driven together along the longitudinal and verticaldirections L, V without any relative motion therebetween.

In yet another non-limiting example, relative motion can occur betweenthe second wedge 52 and each of the third and fourth wedges 53, 54 alongthe longitudinal and vertical directions L, V during substantially theentire second phase of expansion. In this example, in each of theproximal and distal wedge assemblies 124, 126, the reactionary force canoccur at the commencement of the second phase of expansion, causing thefourth ramp 234 to ride along third ramp 190 and the guide protrusion236 of the third wedge 53 to concurrently ride within the guide slot 192as soon as the sixth ramp 268 rides along the first ramp 148.Furthermore, in this example, the guide protrusion 236 of the thirdwedge 53 can abut the stop feature 200 of the second wedge 52substantially at the same time as the external face 178 of the secondwedge 52 abuts the distal end 122 of the nut socket 116.

At the conclusion of the second phase of expansion, in the proximalwedge assembly 124, the external end 172 of the second wedge 52 can besubstantially aligned with the external end 132 of the first wedge 51along the vertical direction V, and, in the distal wedge assembly, theexternal end 172 of the second wedge 52 can be substantially alignedwith the second external face 139′ of the first wedge 51′. Additionally,in each wedge assembly 124, 126, the third and fourth wedges 53, 54 caneach be entirely intermediate the internal and external ends 130, 132 ofthe first wedge 51 as well as the external and internal ends 170, 172 ofthe second wedge 52. Similarly, at the conclusion of the second phase ofexpansion, the downward apex 182 of the second wedge 52 can be spacedupward of the upward apex 140 of the first wedge 51.

Throughout expansion of the implant 10, the respective first wedges 51,51′ of the proximal and distal wedge assemblies 124, 126 can remainadjacent the external ends of the proximal and distal threaded portions104, 106 of the drive shaft 98. Additionally, the second, third andfourth wedges 52, 53, 54 of each wedge assembly 124, 126 can move in theexternal longitudinal direction L_(E) during expansion. Thus, the pointsof contact between the wedge assemblies 124, 126 and the superior andinferior plates 12, 28 are either initially located adjacent theproximal and distal ends 12, 14 of the implant 10 (as in the case of thefirst wedges 51, 51′ coupled to the inferior plate 20) or move towardthe proximal and distal ends 12, 14 of the implant 10 during expansion(as in the case of the second wedges 52 coupled to the superior plate22). Such an arrangement provides enhanced support and stability to theimplant 10 during expansion, particularly with respect to reactiveforces, such as inner body forces, imparted to the implant 10 along thevertical direction V within the intervertebral space 5. However, it isto be appreciated that, in other embodiments (not shown), the respectivefirst wedges 51, 51′ of the proximal and distal wedge assemblies 124,126 can be located adjacent the internal ends of the threaded portions104, 106 of the drive shaft 98, and the second, third and fourth wedges52, 53, 54 of each wedge assembly 124, 126 can move in the internallongitudinal direction L_(I) during expansion.

Operation of the implant 10 to achieve lordosis will now be discussed.

Referring now to FIGS. 38 through 40, the anterior and posterioractuation assemblies 94, 96 can be driven independently in a mannerproviding the implant 10 with a lordotic profile, as set forth above.Stated differently, the anterior and posterior actuation assemblies 94,96 can be operated in a manner causing at least one of the inferior andsuperior plates 20, 22 to tilt relative to the other plate 20, 22 withrespect to the transverse direction T. In some embodiments, at least oneof the plates 20, 22 can tilt relative to the other plate 20, 22 aboutat least one of the first and second central shaft axes X₁. This can beaccomplished by placing the wedge assemblies 124, 126 of one of theanterior and posterior actuation assemblies 94, 96 at a degree ofexpansion that is different than that of the wedge assemblies 124, 126of the other actuation assembly 94, 96. In the example lordoticconfiguration of FIGS. 38 through 40, in the posterior actuationassembly 96, the proximal and distal wedge assemblies 124, 126 thereofcan be at about the collapsed configuration (FIG. 39) while, in theanterior actuation assembly 94, the wedge assemblies 124, 126 thereofcan be expanded to near the first partially expanded configuration, thuscausing the superior plate 22 to tilt relative to the inferior plate 20with respect to the transverse direction T at a lordotic angle β (FIG.40).

When at least one of the plates 20, 22 is tilted lordotically withrespect to the other, a first distance D₁ between the inferior andsuperior bone-contacting surfaces 28, 30, measured along the verticaldirection L and intersecting the central shaft axis X₁ of the anterioractuation assembly 94, can be shorter or longer than a second distanceD₂ between the inferior and superior bone-contacting surfaces 28, 30,measured along the vertical direction L and intersecting the centralshaft axis X₁ of the posterior actuation assembly 96. Additionally, whenat least one of the plates 20, 22 is tilted lordotically with respect tothe other, a vertical distance D₃ between the inferior and superiorplates 20, 22 at the anterior side 16 of the implant 10 can be shorteror longer than a vertical distance D₄ between the plates 20, 22 at theposterior side 18 of the implant 10. As shown in FIG. 40, one of D₃ andD₄ can be as small as zero, at which point the internal contact surfaces46 at the respective side 16, 18 of the implant 10 can define a fulcrum.In some embodiments, the internal faces 44 of the inferior and superiorplate bodies 24, 26 can be curved, canted or can otherwise define a gaptherebetween at one or both of the anterior and posterior sides 16, 18so that at least one of the plates 20, 22 can be tilted lordoticallywhile one of the anterior and posterior actuation assemblies 94, 96 isin the collapsed configuration (i.e., lordosis can be induced from thecollapsed configuration).

It is to be appreciated that the lordotic profile illustrated in FIGS.38 through 40 represents merely one of numerous lordotic profilesachievable with the implant 10 of the present disclosure. For example,the physician can actuate the anterior actuation assembly 94 to a firstexpanded configuration and the posterior actuation assembly 96 to asecond expanded configuration to provide a difference between the firstdistance D₁ and the second distance D₂. In particular, the physician canactuate one of the anterior and posterior actuation assemblies 94, 96 tothe fully expanded configuration while the other actuation assembly 96,94 remains near the fully collapsed configuration to provide the implant10 with a maximum lordotic angle β in the range of about 0 degrees andabout 45 degrees. It is to be appreciated that the physician canindependently place each of the actuation assemblies 94, 96 in thecollapsed configuration, the fully expanded configuration, or anyposition therebetween to provide the implant 10 with the desiredlordotic angle β. It is also to be appreciated that an initial lordoticangle β can be built in to the implant 10. In such embodiments, theinferior and superior bone plates 20, 22 can be configured such that thebone-contacting surfaces 28, 30 thereof are oriented at a lordotic angleβ when the implant 10 is in the collapsed configuration.

The tilting can be rendered possible at least because the inferior plate20 is rotationally interlocked with the first wedge 51, the superiorplate 22 is rotationally interlocked with the second wedge 52, thesecond wedge 52 is rotationally interlocked with the third wedge 53, thethird wedge 53 is rotatable about the respective central shaft axis X₁relative to the fourth wedge 54 (as shown in FIG. 41), and the fourthwedge 54 is rotationally interlocked with the inferior plate 20 (eitherdirectly, as in the first phase of expansion, or via rotationallyinterlocking with the first wedge 51, which is rotationally interlockedwith the inferior plate 20). It is to be appreciated that the fourthwedge 54 acts as a hinge of the implant 10 that facilitates lordotictilting of at least one of the plates 20, 22. By utilizing the driveshaft 98 as the “through pin” of the hinge, the strength of the hinge isincreased and the number of parts needed to complete the hinge isreduced. Additionally, the base surfaces 68 of the channels 56, 58, thebase surfaces 142, 180, 262 of each wedge assembly 124, 126, and theramp surfaces 148, 188, 190, 234, 268 of each wedge assembly 124, 126collaboratively provide the implant 10 with added stability and strengthto withstand inner body forces during and after implantation.

It is also to be appreciated that implant 10 provides the physician withenhanced freedom regarding the sequencing of achieving the desiredexpansion and/or lordosis of the implant 10. In particular, afterpredetermining the desired amount of expansion and/or lordosis of theimplant 10 in the intervertebral space 5, the physician can insert theimplant 10 in the collapsed configuration into the intervertebral space5 along the medial-lateral direction, as shown in FIG. 1. If bothexpansion and lordosis are desired, the physician can expand the implant10 uniformly to a partially expanded configuration, and then expand orretract the implant 10 in a non-uniform manner to achieve the desiredlordotic angle β of the implant 10. The implant 10 can be expanded orretracted non-uniformly in various ways, including, for example:operating one of the actuation assemblies 94, 96 independently;operating both actuation assemblies 94, 96 simultaneously but atdifferent rates; operating both actuation assemblies 94, 96simultaneously but in different rotational directions; or anycombination of the foregoing. The design of the implant 10, as disclosedherein allows the physician to utilize any of the foregoing modes ofexpansion, contraction and/or lordosis to achieve the final desiredconfiguration, and to adjust the configuration of the implant 10 asnecessary, including during subsequent physical procedures on thepatient. The compact nature of the implant 10 in the collapsedconfiguration allows the implant 10 to fit within the standard lumbardisc space. Additionally, because the implant 10 can be adjusted toachieve up to 30 mm or more of expansion and up to 45 degrees or more oflordosis, the physician can use the implant 10 in many differentlocations within the spine and for many different purposes.

Referring now to FIG. 42, a second embodiment of the implant 10′ isshown. It is to be appreciated that the second embodiment can be similarto the first embodiment of the implant shown in FIGS. 1 through 41.Accordingly, the same reference numbers used above with reference to thefirst embodiment can be also used with a “prime” notation in referenceto second embodiment. It is also to be appreciated that, unlessotherwise set forth below, the components (and features thereof) of theimplant 10′ of the second embodiment can be similar to those of thefirst embodiment.

The inferior and superior plates 20′, 22′ of the second embodiment candefine a single vertical aperture 34′ extending through the implant 10′along the vertical direction V. The anterior and posterior portions 36′,38′ of the implant 10 can be located on opposite sides of the verticalaperture 34′. The distal portion 40′ of the implant 10′ can be spacedfrom the vertical aperture 34′ in the distal direction.

Referring now to FIG. 43, the anterior and posterior channels 56′, 58′of each of the inferior and superior plate bodies 24′, 26′ can include aproximal channel portion 55′ that is contoured to match the outercontour of the nut socket 116′. At a distal end of each proximal channelportion 55′, each plate body 24′, 26′ can define a shoulder 57′. Theshoulders 57′ of the inferior plate body 24′ can be configured to abutthe external faces 138′ of the first wedges 51′ of the anterior andposterior actuation assemblies 94′, 96′. The shoulders 57′ of thesuperior plate body 22′ can be configured to abut, or at least beadjacent to, the external faces 178′ of the second wedges 52′ of theactuation assemblies 94′, 96′ when the actuation assemblies 94′, 96′ arein the fully expanded configuration.

Each of the channels 56′, 58′ of the inferior plate body 24′ can definea first pair of cutouts 59′ and a second pair of cutouts 61′ spaced fromeach other along the longitudinal direction L. In each channel 56′, 58′,the cutouts 59′ of the first pair can be opposed to each other along thetransverse direction T, and the cutouts 61′ of the second pair can beopposed to each other along the transverse direction T. While the viewof FIG. 43 only shows the anterior cutout 61′ of each pair, it is to beappreciated that the posterior cutout 61′ of each pair can be a mirrorimage of the associated anterior cutout 61′. The first and second pairsof cutouts 59′, 61′ can each be in communication with the plate guideslots 70′ of the inferior plate body 24′ and can be sized to allow thebase protrusions 142′ of the first wedges 51′ to be inserted into theplate guide slots 70′ during assembly of the implant 10′.

Each of the channels 56′, 58′ of the superior plate body 26′ can definea pair of central cutouts 63′ generally centered with respect to thelongitudinal direction L. In each channel 56′, 58′, the central cutouts63′ of each pair can be opposed to each other along the transversedirection T. While the view of FIG. 43 only shows the posterior centralcutout 63′ of each pair, it is to be appreciated that the anteriorcentral cutout 63′ of each pair can be a mirror image of the associatedposterior central cutout 63′. The central cutouts 63′ can each be incommunication with the plate guide slots 70′ of the superior plate body26′ and can be sized to allow the bottom protrusion 270′ (FIGS. 44through 46) of the fourth wedges 54′ of each actuation assembly 94′, 96′to be inserted into the plate guide slots 70′ during assembly of theimplant 10′.

With continued reference to FIG. 43, each of the plate guide slots 70′can define a proximal end 70 a′ and a distal end 70 b′. In the inferiorplate body 24′, the proximal ends 70 a′ of the plate guide slots 70′ canoptionally be configured to abut the base protrusions of the firstwedges 51″ of the proximal wedge assemblies 124′, and the distal ends 70b′ of the plate guide slots 70′ can optionally be configured to abut thebase protrusions of the first wedges 51′ of the distal wedge assemblies126′. While the base protrusions of the first wedges 51″, 51′ of thepresent embodiment are not visible in FIG. 43, it is to be appreciatedthat these base protrusions can be configured similarly to the baseprotrusions 144, 144′ shown in FIGS. 10 through 15. In the superiorplate body 26′, the proximal ends 70 a′ of the plate guide slots 70′ canoptionally be configured to abut the base protrusions 184′ of the secondwedges 52′ of the proximal wedge assemblies 124′ during operation of theimplant, such as when each respective actuation assembly 94′, 96′ is inthe fully expanded configuration. Similarly, the distal ends 70 b′ ofthe plate guide slots 70′ can optionally be configured to abut the baseprotrusions 184′ of the second wedges 52′ of the distal wedge assemblies126′ during operation of the implant 10′, such as when each respectiveactuation assembly 94′, 96′ is in the fully expanded configuration. Itis to be appreciated that the proximal and distal ends 70 a′, 70 b′ ofthe guide slots 70′ of the superior plate 22 can impede motion of thesecond wedges 52′ in the external longitudinal direction L_(E) duringexpansion of the implant 10.

At the distal portion 40′ of the inferior plate body 24′, the internalface 44′ can define a single transverse slot 73′ elongated along thetransverse direction T. The distal portion 40′ of the superior platebody 26′ can define a single transverse protrusion 83′ protruding beyondthe internal contact surface 46′ of the superior plate body 26′. Whenthe implant 10′ is in the collapsed configuration, the transverseprotrusion 83′ of the superior plate body 26′ can nest within thetransverse slot 73′ of the inferior plate body 24′. The transverseprotrusion 83′ can define a pair of opposed recesses 85′ extending intothe protrusion 83′ along the transverse direction T. The recesses 85′can be configured to receive therein portions of the heads 110′ of thedrive shafts 98′ of the anterior and posterior actuation assemblies 94′,96′, at least when the implant 10′ is in the collapsed configuration.

It is to be appreciated that the third and fourth wedges 53′, 54′ ofeach of the actuation assemblies 94′, 96′ of the second embodiment canbe different than their counterparts in the first embodiment. Referringto FIGS. 44 through 46, the third wedge body 216′ can define an uppersurface 231′ extending between the internal face 226′ and the fourthramp 234′ along the longitudinal direction L. The third wedge body 216′can define a vertical aperture 233′ extending through the fourth ramp234′ and the guide protrusion 236′, and can also define a pair of arms235′, 237′ extending from the internal face 226′ to the external face228′. The vertical aperture 233′ can be in communication with thecentral bore 230′ of the third wedge 53′. A portion of the threading232′ of the central bore 230′ can be defined on the inner sides of thearms 235′, 237′. Each of the pair of arms 235′, 237′ can define a lowersurface 239′ (FIG. 46) that is canted toward the axis X₂ of the centralbore 230′ of the third wedge 53′. The rounded portion 244′ of the thirdwedge 53′ can extend downward from the lower surfaces 239′ of the arms235′, 237′, and can have a substantially semicircular profile in avertical-transverse plane. The rounded portion 244′ of the presentembodiment can optionally not be inclined with respect to thelongitudinal direction L. The rounded portion 244′ can surround at leasta portion of the central bore 230′ of the third wedge body 216′.

The fourth wedge body 246′ can define a front basket 253′ extending fromthe external face 258′ along the external longitudinal direction L_(E).The front basket 253′ can provide the bottom base surface 262 of thefourth wedge body 246′ with increased length and thus increasedstability as the bottom base surface 262 abuts and/or translates alongthe channel base surface 68. The external face 258′ of the fourth wedgebody 246′ can be a first external face thereof, and the front basket253′ can define a second external face 255′ that is spaced from thefirst external face 256′ along the external longitudinal directionL_(E). The second external face 255′ can be positioned at the externalend 250′ of the fourth wedge body 246′. The bottom surface 262′ of thefourth wedge body 246′ can extend from the internal face 256′ to thesixth ramp 268′ along the longitudinal direction L and can extend alonga portion of the basket 253′. The sixth ramp 268′ can extend from thebottom surface 262′ to the second external face 255′ of the fourth wedgebody 246′. The guide protrusion 270′ of the fourth wedge body 246′ ofthe second embodiment can be configured similarly to the guideprotrusion 270′ of the first embodiment.

The basket 253′ can define a central recess 257′ extending along thelongitudinal direction L. The central recess 257′ can be characterizedas an extension of the central bore 264′ of the fourth wedge body 246′along the basket 253′. The central recess 257′ can separate an upperportion of the basket 253′ into a pair of arms 259′, 261′ that eachextend generally along the longitudinal direction L and each have anupper surface 263′ that is canted towards the central bore axis X₃ ofthe fourth wedge 54′. The basket 253′ can also define a trough 265′configured to receive the rounded portion 244′ of the third wedge body216′. The trough 265′ can have a rounded profile that corresponds to theprofile of the rounded portion 244′ of the third wedge body 216′ and canallow the rounded portion 244′ of the third wedge body 216′ to rotatewithin the trough 265 about the central bore axis X₃ of the third wedgebody 216′. The central recess 257′ can also define a portion of thethreading 266′ of the central bore 264′ of the fourth wedge body 246′.The fourth wedge body 216′ can define a vertical aperture 267′ extendingthrough the basket 253′ at the external end 250′ thereof. The verticalapertures 233′, 267′ of the third and fourth wedge bodies 216′, 246′ canbe aligned with one another along the vertical direction V.

As shown in FIGS. 44 and 45, the third wedge body 216′ can be coupled tothe fourth wedge body 54′ such that: the rounded portion 244′ of thethird wedge body 216′ is received within the trough 265′ of the fourthwedge body 246′; the internal face 226′ of the third wedge body 216′abuts or is adjacent to the first external face 256′ of the fourth wedgebody; and the external face 228′ of the third wedge body 216′ issubstantially aligned with the second external face 255′ of the fourthwedge body 246′ along the vertical direction V. When the plates 20′, 22′are at a neutral (i.e., non-lordotic) configuration, a gap 275′ isdefined between the lower surfaces 239′ of the arms 235′, 237′ of thethird wedge body 216′ and the upper surfaces 263′ of the arms 259′, 261′of the fourth wedge body 246′. The gap 275′ and the canted arm surfaces239′, 263′ can be configured to allow the third wedge body 216′ torotate relative to the fourth wedge body 246′, as shown in FIG. 45.Additionally, the rounded portion 244′ of the third wedge body 216′ andthe trough 265′ of the fourth wedge body 246′ can be cooperativelyconfigured to translationally affix the third and fourth wedges 53′, 54′together with respect to translation along the drive shaft 98′.

Referring now to FIG. 47, the second embodiment of the implant 10′ isshown with each wedge assembly 124′, 126′ in the fully expandedconfiguration (with the superior plate 22′ removed for visualizationpurposes). It is to be appreciated that the actuation assemblies 94′,96′ and the wedge assemblies 124′, 126′ of the second embodiment canoperate as set forth above with respect to those of the firstembodiment.

Referring now to FIGS. 48 and 49, the actuation assemblies 94′, 96′ ofthe implant 10′ can be operated independently so that the superior plate22′ is tilted relative to the inferior plate 20′ with respect to thetransverse direction T so as to provide the implant 10′ with a lordoticprofile, as set forth above. As shown in FIG. 48, the inferior andsuperior bone-contacting surfaces 28′, 30′ can be oriented at a lordoticangle β in the range of about 0 degrees and about 25 degrees. As setforth above, when at least one of the plates 20′, 22′ is tiltedlordotically with respect to the other, a first vertical distance D₁between the inferior and superior bone-contacting surfaces 28′, 30′ thatintersects the associated central shaft axis X₁ can be shorter or longerthan a second vertical distance D₂ between the bone-contacting surfaces28′, 30′ that intersects the associated central shaft axis X₁.Additionally, when at least one of the plates 20′, 22′ is tiltedlordotically with respect to the other, a vertical distance D₃ betweenthe inferior and superior plates 20′, 22′ at the anterior side 16′ ofthe implant 10′ can be shorter or longer than a vertical distance D₄between the plates 20′, 22′ at the posterior side 18′ of the implant 10,as set forth above.

As shown in the example lordotic configuration of FIG. 49, in theanterior actuation assembly 94′, the proximal and distal wedgeassemblies 124′, 126′ thereof can be near the collapsed configurationwhile, in the posterior actuation assembly 96′, the wedge assemblies124′, 126′ thereof can be expanded near or at the fully expandedconfiguration, thus causing the lordotic tilting of the superior plate22′. It is to be appreciated that, while FIG. 49 illustrates theinferior and superior plates 20′, 22′ separated vertically to provide anunobstructed view of the actuation assemblies 94′, 96′, the plates 20′,22′ are shown at the same lordotic angle β as in FIG. 48.

It is to be appreciated that, while the illustrated embodiments depictthe implant 10 having a pair of actuation assemblies 94, 96, in otherembodiments (not shown), the implant 10 can have a single actuationassembly 94 to expand the implant 10 along the vertical direction V. Inone such embodiment, the plates 20, 22 can be configured to maintaincontact with each other in a hinge-like manner at one of the anteriorand posterior sides 16, 18 so that operation of the single actuationassembly 94 expands the implant 10 vertically and simultaneouslyprovides lordosis.

Referring now to FIG. 50, a driving tool 300 can be configured to engagethe anterior and posterior actuation assemblies 94, 96 of the implant10. For example, the driving tool 300 can include a handle 302 coupledto a first driver 304 and a second driver 306 that are spaced from eachother along the transverse direction T. The first driver 304 can carry afirst bit 308 configured to engage the drive coupling of the anterioractuation assembly 94 while the second driver 306 can carry a second bit310 configured to engage the drive coupling of the posterior actuationassembly 96. For example, in the illustrated embodiments, the first andsecond bits 308, 310 can each define a hex profile configured to engagea corresponding hex profile of the socket aperture 118 of thecorresponding actuation assembly 94, 96.

The driving tool 300 can include a one or more selector switches thatallows the physician to select between various modes of operation of thetool 300. For example, a first selector switch 312 can toggle between afirst drive mode A, a second drive mode B, and a third drive mode C. Inthe first drive mode A, the tool 300 can be set to operate only thefirst driver 304. In the second drive mode B, the tool 300 can be set tooperate the first and second drivers 304, 306 simultaneously. In thethird mode C, the tool 300 can be set to operate only the second driver306.

A second selector switch 314 can be in communication with the firstdriver 304. For example, the second selector switch 314 can togglebetween a first position E, wherein the tool 300 is set to rotate thefirst driver 304 in the clockwise direction, and a second position F,wherein the tool 300 is set to rotate the first driver 304 in thecounterclockwise direction. Similarly, a third selector switch 316 canbe in communication with the second driver 306. For example, the thirdselector switch 316 can toggle between a first position G, wherein thetool 300 is set to rotate the second driver 306 in the clockwisedirection, and a second position H, wherein the tool 300 is set torotate the second driver 306 in the counterclockwise direction.

A fourth selector switch 318 can allow the physician to select a torqueand/or speed setting of the first driver 304. A fifth selector switch320 can allow the physician to select a torque and/or speed setting ofthe second driver 306. Accordingly, the first, second, third, fourth,and fifth selector switches 312, 314, 316, 318, 320 allow the physicianto use the tool 300 to operate the anterior and posterior actuationassemblies 94, 96 uniformly or independently as desired. Additionally,the selector switches can also allow the physician to tailor therotational direction, speed and/or torque of each of the actuationassemblies 94, 96 independently.

Although the disclosure has been described in detail, it should beunderstood that various changes, substitutions, and alterations can bemade herein without departing from the spirit and scope of the inventionas defined by the appended claims. Additionally, any of the embodimentsdisclosed herein can incorporate features disclosed with respect to anyof the other embodiments disclosed herein. Moreover, the scope of thepresent disclosure is not intended to be limited to the particularembodiments described in the specification. As one of ordinary skill inthe art will readily appreciate from that processes, machines,manufacture, composition of matter, means, methods, or steps, presentlyexisting or later to be developed that perform substantially the samefunction or achieve substantially the same result as the correspondingembodiments described herein may be utilized according to the presentdisclosure.

What is claimed:
 1. An intervertebral implant configured to iteratebetween a collapsed configuration and an expanded configuration, theimplant comprising: a first plate and a second plate spaced from oneanother along a first direction, the first plate defining a firstbone-contacting surface, the second plate defining a secondbone-contacting surface facing away from the first bone-contactingsurface along the first direction; an expansion assembly disposedbetween the first and second plates with respect to the first direction,the expansion assembly including: a first support wedge supporting thefirst plate, the first support wedge defining a first ramp; a secondsupport wedge supporting the second plate, the second support wedgedefining a second ramp and a third ramp; and an expansion wedge defininga fourth ramp, wherein each of the first, second, third, and fourthramps is inclined with respect to a second direction that issubstantially perpendicular to the first direction, and at least one ofthe first and second support wedges is slidable along the respectivesupported first or second plate; and an actuator configured to apply adrive force to the expansion wedge so as to cause 1) the fourth ramp toride along the third ramp so as to increase a distance between the firstand second bone-contacting surfaces along the first direction, and 2)the second ramp to ride along the first ramp, thereby further increasingthe distance, thereby iterating the implant from the collapsedconfiguration to the expanded configuration, wherein the first andsecond support wedges and the expansion wedge are translatable relativeto each other.
 2. The implant of claim 1, wherein the distance increasesat least by a factor of 2.0 between the collapsed and expandedconfigurations.
 3. The implant of claim 1, wherein each of the first,second, third, and fourth ramps is inclined at an incline angle in therange of 10 degrees to 60 degrees.
 4. The implant of claim 3, whereinthe expansion wedge defines an additional ramp configured to ride alongthe first ramp responsive to the drive force, and the additional ramp isinclined at an angle in the range of 20 degrees to 50 degrees.
 5. Theimplant of claim 1, wherein the actuator is rotatable about an axisoriented along the second direction, and the actuator drives theexpansion wedge to translate along the second direction as the fourthramp rides along the third ramp.
 6. The implant of claim 1, wherein theactuator is threadedly coupled to the expansion wedge, such thatrotation of the actuator about the axis causes the expansion wedge tothreadedly translate along the actuator.
 7. The implant of claim 1,wherein: the expansion assembly is a first expansion assembly; and theimplant further comprises a second expansion assembly disposed betweenthe first and second plates with respect to the first direction, thesecond expansion assembly spaced from the first expansion assembly alongthe second direction, the second expansion assembly including: a thirdsupport wedge supporting the first plate, the third support wedgedefining a fifth ramp; a fourth support wedge supporting the secondplate, the second support wedge defining a sixth ramp and a seventhramp; and a second expansion wedge defining an eighth ramp, wherein eachof the fifth, sixth, seventh, and eighth ramps is inclined with respectto the second direction, and at least one of the third and fourthsupport wedges is slidable along the respective supported first orsecond plate, and the actuator is configured to apply a second driveforce to the second expansion wedge so as to cause 1) the eighth ramp toride along the seventh ramp as the fourth ramp rides along the thirdramp so as to collectively increase the distance between the first andsecond plates along the first direction, and 2) the sixth ramp to ridealong the fifth ramp as the second ramp rides along the first ramp so asto collectively further increasing the distance between the first andsecond plates along the first direction, thereby iterating the implantfrom the collapsed configuration to the expanded configuration.
 8. Theimplant of claim 1, wherein the expanded configuration is a firstexpanded configuration, expansion assembly is a first expansionassembly, the distance is a first distance, and the implant furthercomprises: a first side and a second side spaced from the first sidealong a third direction that is substantially perpendicular to the firstand second directions, wherein the first distance is measurable at thefirst side of the implant; a second expansion assembly disposed betweenthe first and second plates with respect to the first direction, thesecond expansion assembly spaced from the first expansion assembly alongthe third direction, the second expansion assembly including: a thirdsupport wedge supporting the first plate, the third support wedgedefining a fifth ramp; a fourth support wedge supporting the secondplate, the second support wedge defining a sixth ramp and a seventhramp; and a second expansion wedge defining an eighth ramp, wherein eachof the fifth, sixth, seventh, and eighth ramps is inclined with respectto the second direction, and at least one of the third and fourthsupport wedges is slidable along the respective plate supported by theone of the third and fourth support wedges; and a second actuatorconfigured to apply a second drive force to the second expansion wedgeso as to cause 1) the eighth ramp to ride along the seventh ramp so asto increase a second distance between the first and second plates alongthe first direction, wherein the second distance is measurable at thesecond side, and 2) the sixth ramp to ride along the fifth ramp so as tofurther increasing the second distance between the first and secondplates along the first direction, thereby iterating the implant from thecollapsed configuration to the second expanded configuration, wherein,in the second expanded configuration, the second distance is differentthan the first distance such that one of the first and second plates istilted with respect to the other of the first and second plate.
 9. Anintervertabral implant configured to iterate between a collapsedconfiguration and an expanded configuration, the implant comprising: afirst plate and a second plate spaced from one another along a firstdirection, the first plate defining a first bone-contacting surface, thesecond plate defining a second bone-contacting surface facing away fromthe first bone-contacting surface along the first direction; anexpansion assembly disposed between the first and second plates withrespect to the first direction, the expansion assembly including: afirst support wedge supporting the first plate, the first support wedgedefining a first ramp; the second support wedge supporting the secondplate, the second support wedge defining a second ramp and a third ramp;and an expansion wedge defining a fourth ramp, wherein each of thefirst, second, third, and fourth ramps is inclined with respect to asecond direction that is substantially perpendicular to the firstdirection, and at least one of the first and second support wedges isslidable along the respective supported first or second plate; and anactuator configured to apply a drive force to the expansion wedge so asto cause 1) the fourth ramp to ride along the third ramp so as toincrease a distance between the first and second bone-contactingsurfaces along the first direction, and 2) the second ramp to ride alongthe first ramp, thereby further increasing the distance, therebyiterating the implant from the collapsed configuration to the expandedconfiguration, wherein: when the implant is in the collapsedconfiguration, an entirety of the first support wedge is spaced from anentirety of the expansion wedge with respect to the second direction,and at least a portion of the second support wedge is disposed betweenthe first support wedge and the expansion wedge with respect to thesecond direction; and when the implant is in the expanded configuration,the first support wedge underlies an entirety of the expansion wedgewith respect to the first direction, and an entirety of the secondsupport wedge is spaced from an entirety of the first support wedge withrespect to the first direction.
 10. The implant of claim 9, wherein thefirst plate defines a first channel elongate along the second direction,the second plate defines a second channel elongate along the seconddirection, the first and second channels are open toward one another andoverly one another so as to define a compartment, and each of the wedgesis housed within the compartment when the implant is in the collapsedconfiguration.
 11. The implant of claim 10, wherein: the first channeldefines a first base surface extending along the second direction and athird direction that is perpendicular to the first and seconddirections; the second channel defines a second base surface extendingalong the second and third directions, and the first and second basesurfaces face one another; the second support wedge defines a wedge basesurface that is configured to slide along the second base surface duringexpansion of the implant between the collapsed configuration and theexpanded configuration, and the expansion wedge defines another wedgebase surface that is configured to ride along the first base surfaceduring expansion of the implant.
 12. The implant of claim 11, whereinthe expansion wedge further defines an additional ramp that is inclinedwith respect to the second direction, and the implant is configured suchthat, during a first phase of expansion of the implant: the additionalramp is remote from the first ramp with respect to the second directionwhile the second ramp rides along the first ramp and; the fourth ramprides along the third ramp; and the another wedge base surface ridesalong the first base surface.
 13. The implant of claim 12, wherein theimplant is configured such that, during a second phase of expansion ofthe implant, 1) the additional ramp rides along the first ramp, and 2)the second ramp is remote from the first ramp.
 14. An implant forlateral insertion into an intervertebral space, the implant comprising:an expansion mechanism disposed between a first endplate and a secondendplate with respect to a vertical direction, the first endplatedefining a first-bone contacting surface, the second endplate defining asecond bone-contacting surface facing away from the firstbone-contacting surface along the vertical direction, the expansionmechanism comprising: an anterior actuation assembly arranged along afirst axis; and a posterior actuation assembly arranged along a secondaxis, the first and second axes each oriented along a longitudinaldirection that is substantially perpendicular to the vertical direction,the first and second axes spaced from one another along a transversedirection that is substantially perpendicular to the vertical andlongitudinal directions, wherein a first distance between the first andsecond bone-contacting surfaces along the vertical direction intersectsthe first axis, and a second distance between the first and secondbone-contacting surfaces along the vertical direction intersects thesecond axis, the anterior and posterior actuation assemblies eachcomprising: a first support wedge that supports the first endplate; asecond support wedge that supports the second endplate, the secondsupport wedge slidable with respect to the first support wedge; and anexpansion wedge slidable with respect to the second support wedge; and adrive shaft coupled to the expansion wedge, the drive shaft rotatableabout the respective first or second axis so as to cause 1) theexpansion wedge to ride along the second support wedge, and 2) thesecond support wedge to ride along the first support wedge, therebyvarying the respective first or second distance; wherein the driveshafts of the anterior and posterior actuation assemblies are rotatableindependently of each other so as to provide a difference between thefirst and second distances.
 15. The implant of claim 14, wherein eachexpansion wedge comprises a first member and a second member, the firstmember is rotatable with respect to the second member about therespective first or second axis, and the first member is configured toride along the respective second support wedge responsive to rotation ofthe respective drive shaft, and the second member is configured to ridealong the respective first support wedge responsive to rotation of therespective drive shaft.
 16. The implant of claim 15, wherein: eachendplate defines an anterior guide feature and a posterior guidefeature, each of the anterior and posterior guide features extendingalong the longitudinal direction, each second support wedge includes aguide element configured to ride along the respective anterior orposterior guide feature of the second endplate; and the second member ofeach expansion wedge includes a guide element configured to ride alongthe respective anterior or posterior guide feature of the firstendplate.
 17. The implant of claim 16, wherein each second support wedgefurther includes a guide feature, and the first member of each expansionwedge defines a guide element configured to ride within the guidefeature of the respective second support wedge.
 18. The implant of claim17, wherein each first support wedge defines a guide feature, and theguide element of the respective second member is further configured toride along the guide feature of the respective first support wedge. 19.The implant of claim 18, wherein each of the guide features is a guideslot, and each of the guide elements is a guide protrusion configured toextend within and ride along the associated guide slot.
 20. The implantof claim 19, wherein: the guide slots of the second endplate and therespective guide protrusions of the second support wedges arecooperatively shaped so as to rotationally interlock the second endplateto each of the second support wedges with respect to rotation about therespective first or second axis; and the guide slots of the secondsupport wedges and the respective guide protrusions of the first membersare cooperatively shaped so as to rotationally interlock the secondsupport wedges to the respective first members with respect to rotationabout the respective first or second axis.
 21. The implant of claim 20,wherein, each first support wedge is fixed to the first endplate withrespect to rotation about the respective first or second axis; the guideprotrusion of each second member and the respective guide slot of thefirst endplate are cooperatively shaped so as to rotationally interlockthe first endplate to the associated second member when the guideprotrusion of the associated second member extends within the respectiveguide slot; and the guide protrusion of each second member and the guideslot of the respective first support wedge are cooperatively shaped soas to rotationally interlock each first support wedge to the associatedsecond member when the guide protrusion of the associated second memberextends within the guide slot of the associated first support wedge.